fix: <Transition/> with local_resource (closes #562)

Co-authored-by: Denis Nazarov <denis.nazarov@gmail.com>

.github/workflows/test.yml

@@ -30,6 +30,9 @@ jobs:
           override: true
           components: rustfmt
 
+      - name: Add wasm32-unknown-unknown
+        run: rustup target add wasm32-unknown-unknown
+
       - name: Setup cargo-make
         uses: davidB/rust-cargo-make@v1
 
@@ -43,4 +46,3 @@ jobs:
 
       - name: Run tests with all features
         run: cargo make ci
-

Cargo.toml

@@ -11,30 +11,28 @@ members = [
   # integrations
   "integrations/actix",
   "integrations/axum",
+  "integrations/viz",
+  "integrations/utils",
 
   # libraries
   "meta",
   "router",
-
-  # book
-  "docs/book/project/ch02_getting_started",
-  "docs/book/project/ch03_building_ui",
-  "docs/book/project/ch04_reactivity",
 ]
 exclude = ["benchmarks", "examples"]
 
 [workspace.package]
-version = "0.1.1"
+version = "0.2.0-beta"
 
 [workspace.dependencies]
-leptos = { path = "./leptos", default-features = false, version = "0.1.1" }
-leptos_dom = { path = "./leptos_dom", default-features = false, version = "0.1.1" }
-leptos_macro = { path = "./leptos_macro", default-features = false, version = "0.1.1" }
-leptos_reactive = { path = "./leptos_reactive", default-features = false, version = "0.1.1" }
-leptos_server = { path = "./leptos_server", default-features = false, version = "0.1.1" }
-leptos_config = { path = "./leptos_config", default-features = false, version = "0.1.1" }
-leptos_router = { path = "./router", version = "0.1.1" }
-leptos_meta = { path = "./meta", default-feature = false, version = "0.1.1" }
+leptos = { path = "./leptos", default-features = false, version = "0.2.0-beta" }
+leptos_dom = { path = "./leptos_dom", default-features = false, version = "0.2.0-beta" }
+leptos_macro = { path = "./leptos_macro", default-features = false, version = "0.2.0-beta" }
+leptos_reactive = { path = "./leptos_reactive", default-features = false, version = "0.2.0-beta" }
+leptos_server = { path = "./leptos_server", default-features = false, version = "0.2.0-beta" }
+leptos_config = { path = "./leptos_config", default-features = false, version = "0.2.0-beta" }
+leptos_router = { path = "./router", version = "0.2.0-beta" }
+leptos_meta = { path = "./meta", default-feature = false, version = "0.2.0-beta" }
+leptos_integration_utils = { path = "./integrations/utils", version = "0.2.0-beta" }
 
 [profile.release]
 codegen-units = 1

Makefile.toml

@@ -8,33 +8,40 @@
 default_to_workspace = false
 
 [tasks.ci]
-dependencies = ["build", "build-examples", "test"]
+dependencies = ["build", "check-examples", "test"]
 
 [tasks.build]
 clear = true
-dependencies = ["build-all"]
+dependencies = ["build-all", "build-wasm"]
 
 [tasks.build-all]
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
 
-[tasks.build-examples]
+[tasks.build-wasm]
+clear = true
+dependencies = [{ name = "build-wasm", path = "leptos" }]
+
+[tasks.check-examples]
 clear = true
 dependencies = [
-	{ name = "build", path = "examples/counter" },
-	{ name = "build", path = "examples/counter_isomorphic" },
-	{ name = "build", path = "examples/counters" },
-	{ name = "build", path = "examples/counters_stable" },
-	{ name = "build", path = "examples/fetch" },
-	{ name = "build", path = "examples/hackernews" },
-	{ name = "build", path = "examples/hackernews_axum" },
-	{ name = "build", path = "examples/parent_child" },
-	{ name = "build", path = "examples/router" },
-	{ name = "build", path = "examples/tailwind" },
-	{ name = "build", path = "examples/todo_app_sqlite" },
-	{ name = "build", path = "examples/todo_app_sqlite_axum" },
-	{ name = "build", path = "examples/todomvc" },
+	{ name = "check", path = "examples/counter" },
+	{ name = "check", path = "examples/counter_isomorphic" },
+	{ name = "check", path = "examples/counter_without_macros" },
+	{ name = "check", path = "examples/counters" },
+	{ name = "check", path = "examples/counters_stable" },
+	{ name = "check", path = "examples/errors_axum" },
+	{ name = "check", path = "examples/fetch" },
+	{ name = "check", path = "examples/hackernews" },
+	{ name = "check", path = "examples/hackernews_axum" },
+	{ name = "check", path = "examples/parent_child" },
+	{ name = "check", path = "examples/router" },
+	{ name = "check", path = "examples/tailwind" },
+	{ name = "check", path = "examples/todo_app_sqlite" },
+	{ name = "check", path = "examples/todo_app_sqlite_axum" },
+	{ name = "check", path = "examples/todo_app_sqlite_viz" },
+	{ name = "check", path = "examples/todomvc" },
 ]
 
 [tasks.test]

README.md

@@ -78,7 +78,7 @@ rustup target add wasm32-unknown-unknown
 
 If you’re on `stable`, note the following:
 
-1. You need to enable the `"stable"` flag in `Cargo.toml`: `leptos = { version = "0.1.0-alpha", features = ["stable"] }`
+1. You need to enable the `"stable"` flag in `Cargo.toml`: `leptos = { version = "0.1.0", features = ["stable"] }`
 2. `nightly` enables the function call syntax for accessing and setting signals. If you’re using `stable`,
    you’ll just call `.get()`, `.set()`, or `.update()` manually. Check out the
    [`counters_stable` example](https://github.com/leptos-rs/leptos/blob/main/examples/counters_stable/src/main.rs)
@@ -99,6 +99,10 @@ Open browser on [http://localhost:3000/](http://localhost:3000/)
 
 ## FAQs
 
+### What’s up with the name?
+
+*Leptos* (λεπτός) is an ancient Greek word meaning “thin, light, refine, fine-grained.” To me, a classicist and not a dog owner, it evokes the lightweight reactive system that powers the framework. I've since learned the same word is at the root of the medical term “leptospirosis,” a blood infection that affects humans and animals... My bad. No dogs were harmed in the creation of this framework.
+
 ### Is it production ready?
 
 People usually mean one of three things by this question.

docs/book/.gitignore

@@ -1 +1 @@
-book
+book

docs/book/README.md

@@ -0,0 +1,14 @@
+This project contains the core of a new introductory guide to Leptos.
+
+It is built using `mdbook`. You can view a local copy by installing `mdbook`
+
+```bash
+cargo install mdbook
+```
+
+and run the book with
+```
+mdbook serve
+```
+
+It should be available at `http://localhost:3000`.

docs/book/book.toml

@@ -1,16 +0,0 @@
-[book]
-authors = ["Greg Johnston"]
-language = "en"
-multilingual = false
-src = "src"
-title = "The Leptos Guide"
-
-[preprocessor]
-
-[preprocessor.mermaid]
-command = "mdbook-mermaid"
-
-[output]
-
-[output.html]
-additional-js = ["mermaid.min.js", "mermaid-init.js"]

docs/book/mermaid-init.js

@@ -1 +0,0 @@
-mermaid.initialize({startOnLoad:true});

docs/book/project/ch02_getting_started/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "ch02_getting_started"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
-leptos = "0.0.18"

docs/book/project/ch02_getting_started/index.html

@@ -1,14 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-	<head>
-		<meta charset="utf-8" />
-		<meta name="viewport" content="width=device-width, initial-scale=1" />
-		<title>Leptos • Todos</title>
-
-		<!-- This custom link tag with `data-trunk` tells Trunk to insert code here to load our Rust/Wasm code -->
-		<!-- `data-wasm-opt=z` tells the compiler to optimize for binary size in a release build -->
-		<link data-trunk rel="rust" data-wasm-opt="z" />
-
-	</head>
-	<body></body>
-</html>

docs/book/project/ch02_getting_started/src/main.rs

@@ -1,5 +0,0 @@
-use leptos::*;
-
-fn main() {
-    mount_to_body(|_cx| view! { cx,  <p>"Hello, world!"</p> })
-}

docs/book/project/ch03_building_ui/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "ch03_building_ui"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
-leptos = "0.0.18"

docs/book/project/ch03_building_ui/index.html

@@ -1,14 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-	<head>
-		<meta charset="utf-8" />
-		<meta name="viewport" content="width=device-width, initial-scale=1" />
-		<title>Leptos • Todos</title>
-
-		<!-- This custom link tag with `data-trunk` tells Trunk to insert code here to load our Rust/Wasm code -->
-		<!-- `data-wasm-opt=z` tells the compiler to optimize for binary size in a release build -->
-		<link data-trunk rel="rust" data-wasm-opt="z" />
-
-	</head>
-	<body></body>
-</html>

docs/book/project/ch03_building_ui/src/main.rs

@@ -1,39 +0,0 @@
-use leptos::*;
-
-fn main() {
-    mount_to_body(|cx| {
-        let name = "gbj";
-        let userid = 0;
-        let _input_element: Element;
-
-        view! {
-            cx,
-            <main>
-                <h1>"My Tasks"</h1>     // text nodes are wrapped in quotation marks
-                <h2>"by " {name}</h2>
-                <input
-                    type="text"         // attributes work just like they do in HTML
-                    name="new-todo"
-                    prop:value="todo"   // `prop:` lets you set a property on a DOM node
-                    value="initial"     // side note: the DOM `value` attribute only sets *initial* value
-                                        // this is very important when working with forms!
-                    _ref=_input_element // `_ref` stores tis element in a variable
-                />
-                <ul data-user=userid>   // attributes can take expressions as values
-                    <li class="todo my-todo" // here we set the `class` attribute
-                        class:completed=true // `class:` also lets you toggle individual classes
-                        on:click=|_| todo!() // `on:` adds an event listener
-                    >
-                        "Buy milk."
-                    </li>
-                    <li class="todo my-todo" class:completed=false>
-                        "???"
-                    </li>
-                    <li class="todo my-todo" class:completed=false>
-                        "Profit!!!"
-                    </li>
-                </ul>
-            </main>
-        }
-    })
-}

docs/book/project/ch04_reactivity/Cargo.toml

@@ -1,7 +0,0 @@
-[package]
-name = "ch04_reactivity"
-version = "0.1.0"
-edition = "2021"
-
-[dependencies]
-leptos = "0.0.18"

docs/book/project/ch04_reactivity/src/main.rs

@@ -1,28 +0,0 @@
-use leptos::*;
-
-fn main() {
-    run_scope(create_runtime(), |cx| {
-        // signal
-        let (count, set_count) = create_signal(cx, 1);
-
-        // derived signal
-        let double_count = move || count() * 2;
-
-        // memo
-        let memoized_square = create_memo(cx, move |_| count() * count());
-
-        // effect
-        create_effect(cx, move |_| {
-            println!(
-                "count =\t\t{} \ndouble_count = \t{}, \nsquare = \t{}",
-                count(),
-                double_count(),
-                memoized_square()
-            );
-        });
-
-        set_count(1);
-        set_count(2);
-        set_count(3);
-    });
-}

docs/book/src/01_introduction.md

@@ -1,10 +1,19 @@
 # Introduction
 
-This book is intended as an introduction to the [Leptos](https://github.com/leptos-rs/leptos) Web framework. Together, we’ll build a simple todo app—first as a client-side app, then as a full-stack app.
+This book is intended as an introduction to the [Leptos](https://github.com/leptos-rs/leptos) Web framework. 
+It will walk through the fundamental concepts you need to build applications, 
+beginning with a simple application rendered in the browser, and building toward a
+full-stack application with server-side rendering and hydration.
 
-The guide doesn’t assume you know anything about fine-grained reactivity or the details of modern Web frameworks. It does assume you are familiar with the Rust programming language, HTML, CSS, and the DOM and other Web APIs.
+The guide doesn’t assume you know anything about fine-grained reactivity or the 
+details of modern Web frameworks. It does assume you are familiar with the Rust 
+programming language, HTML, CSS, and the DOM and basic Web APIs.
 
-Leptos is most similar to frameworks like [Solid](https://www.solidjs.com) (JavaScript) and [Sycamore](https://sycamore-rs.netlify.app/) (Rust). There are some similarities to other frameworks like React (JavaScript), Yew (Rust), and Dioxus (Rust), so knowledge of one of those frameworks may also make it easier to understand Leptos.
+Leptos is most similar to frameworks like [Solid](https://www.solidjs.com) (JavaScript) 
+and [Sycamore](https://sycamore-rs.netlify.app/) (Rust). There are some similarities 
+to other frameworks like React (JavaScript), Svelte (JavaScript), Yew (Rust), and 
+Dioxus (Rust), so knowledge of one of those frameworks may also make it easier to 
+understand Leptos.
 
 You can find more detailed docs for each part of the API at [Docs.rs](https://docs.rs/leptos/latest/leptos/).
 

docs/book/src/02_getting_started.md

@@ -1,37 +1,48 @@
 # Getting Started
 
-> The code for this chapter can be found [here](https://github.com/leptos-rs/leptos/tree/main/docs/book/project/ch02_getting_started).
+There are two basic paths to getting started with Leptos:
+1. Client-side rendering with [Trunk](https://trunkrs.dev/)
+2. Full-stack rendering with [`cargo-leptos`](https://github.com/leptos-rs/cargo-leptos)
+
+For the early examples, it will be easiest to begin with Trunk. We’ll introduce
+`cargo-leptos` a little later in this series.
 
-The easiest way to get started using Leptos is to use [Trunk](https://trunkrs.dev/), as many of our [examples](https://github.com/leptos-rs/leptos/tree/main/examples) do. (Trunk is a simple build tool that includes a dev server.)
 
 If you don’t already have it installed, you can install Trunk by running
 
 ```bash
-cargo install --lock trunk
+cargo install trunk
 ```
 
 Create a basic Rust binary project
 
 ```bash
-cargo init leptos-todo
+cargo init leptos-tutorial
 ```
 
-Add `leptos` as a dependency to your `Cargo.toml` with the `csr` featured enabled. (That stands for “client-side rendering.” We’ll talk more about Leptos’s support for server-side rendering and hydration later.)
-
-```toml
-leptos = "0.0"
+`cd` into your new `leptos-tutorial` project and add `leptos` as a dependency 
+```bash
+cargo add leptos
 ```
 
-You’ll want to set up a basic `index.html` with the following content:
-
+Create a simple `index.html` in the root of the `leptos-tutorial` directory
 ```html
-{{#include ../project/ch02_getting_started/index.html}}
+<!DOCTYPE html>
+<html>
+  <head></head>
+  <body></body>
+</html>
 ```
 
-Let’s start with a very simple `main.rs`
+And add a simple “Hello, world!” to your `main.rs`
+```rust 
+use leptos::*;
 
-```rust
-{{#include ../project/ch02_getting_started/src/main.rs}}
+fn main() {
+    mount_to_body(|_cx| view! { cx,  <p>"Hello, world!"</p> })
+}
 ```
 
-Now run `trunk serve --open`. Trunk should automatically compile your app and open it in your default browser. If you make edits to `main.rs`, Trunk will recompile your source code and live-reload the page.
+Now run `trunk serve --open`. Trunk should automatically compile your app and 
+open it in your default browser. If you make edits to `main.rs`, Trunk will 
+recompile your source code and live-reload the page.

docs/book/src/03_building_ui.md

@@ -1,49 +0,0 @@
-# Templating: Building User Interfaces
-
-> The code for this chapter can be found [here](https://github.com/leptos-rs/leptos/tree/main/docs/book/project/ch03_building_ui).
-
-## RSX and the `view!` macro
-
-Okay, that “Hello, world!” was a little boring. We’re going to be building a todo app, so let’s look at something a little more complicated.
-
-As you noticed in the first example, Leptos lets you describe your user interface with a declarative `view!` macro. It looks something like this:
-
-```
-view! {
-	cx, // this is the "reactive scope": more on that in the next chapter
-	<p>"..."</p> // this is some HTML-ish stuff
-}
-```
-
-The “HTML-ish stuff” is what we call “RSX”: XML in Rust. (You may recognize the similarity to JSX, which is the mixed JavaScript/XML syntax used by frameworks like React.)
-
-Here’s a more in-depth example:
-
-```rust
-{{#include ../project/ch03_building_ui/src/main.rs}}
-```
-
-You’ll probably notice a few things right away:
-
-1. Elements without children need to be explicit closed with a `/` (`<input/>`, not `<input>`)
-2. Text nodes are formatted as strings, i.e., wrapped in quotation marks (`"My Tasks"`)
-3. Dynamic blocks can be inserted as children of elements, if wrapped in curly braces (`<h2>"by " {name}</h2>`)
-4. Attributes can be given Rust expressions as values. This could be a string literal as in HTML (`<input type="text" .../>)` or a variable or block (`data-user=userid` or `on:click=move |_| { ... }`)
-5. Unlike in HTML, whitespace is ignored and should be manually added (it’s `<h2>"by " {name}</h2>`, not `<h2>"by" {name}</h2>`; the space between `"by"` and `{name}` is ignored.)
-6. Normal attributes work exactly like you'd think they would.
-7. There are also special, prefixed attributes.
-
-- `class:` lets you make targeted updates to a single class
-- `on:` lets you add an event listener
-- `prop:` lets you set a property on a DOM element
-- `_ref` stores the DOM element you’re creating in a variable
-
-> You can find more information in the [reference docs for the `view!` macro](https://docs.rs/leptos/0.0.15/leptos/macro.view.html).
-
-## But, wait...
-
-This example shows some parts of the Leptos templating syntax. But it’s completely static.
-
-How do you actually make the user interface interactive?
-
-In the next chapter, we’ll talk about “fine-grained reactivity,” which is the core of the Leptos framework.

docs/book/src/04_reactivity.md

@@ -1,240 +0,0 @@
-# Reactivity
-
-## What is reactivity?
-
-A few months ago, I completely baffled a friend by trying to explain what I was working on. “You have two variables, right? Call them `a` and `b`. And then you have a third variable, `c`. And when you update `a` or `b`, the value of `c` just _automatically changes_. And it changes _on the screen_! Automatically!”
-
-“Isn’t that just... how computers work?” she asked me, puzzled. If your programming experience is limited to something like spreadsheets, it’s a reasonable enough assumption. This is, after all, how math works.
-
-But you know this isn't how ordinary imperative programming works.
-
-```rust,should_panic
-let mut a = 0;
-let mut b = 0;
-let c = a + b;
-
-assert_eq!(c, 0); // sanity check
-
-a = 2;
-b = 2;
-
-// now c = 4, right?
-assert_eq!(c, 4); // nope. we all know this is wrong!
-```
-
-But that’s _exactly_ how reactive programming works.
-
-```rust
-use leptos::*;
-
-run_scope(create_runtime(), |cx| {
-    let (a, set_a) = create_signal(cx, 0);
-    let (b, set_b) = create_signal(cx, 0);
-    let c = move || a() + b();
-
-    assert_eq!(c(), 0); // yep, still true
-
-    set_a(2);
-    set_b(2);
-
-    assert_eq!(c(), 4); // ohhhhh yeah.
-});
-```
-
-Hopefully, this makes some intuitive sense. After all, `c` is a closure. Calling it again causes it to access its values a second time. This isn’t _that_ cool.
-
-```rust
-use leptos::*;
-
-run_scope(create_runtime(), |cx| {
-    let (a, set_a) = create_signal(cx, 0);
-    let (b, set_b) = create_signal(cx, 0);
-    let c = move || a() + b();
-
-    create_effect(cx, move |_| {
-        println!("c = {}", c()); // prints "c = 0"
-    });
-
-    set_a(2); // prints "c = 2"
-    set_b(2); // prints "c = 4"
-});
-```
-
-This example’s a little different. [`create_effect`](https://docs.rs/leptos/latest/leptos/fn.create_effect.html) defines a “side effect,” a bridge between the reactive system of signals and the outside world. Effects synchronize the reactive system with everything else: the console, the filesystem, an HTTP request, whatever.
-
-Because the closure `c` is called within the effect and in turns calls the signals `a` and `b`, the effect automatically subscribes to the signals `a` and `b`. This means that whenever `a` or `b` is updated, the effect will re-run, logging the value again.
-
-You can picture the reactive graph for this system like this:
-
-```mermaid
-graph TD;
-    A-->C;
-    B-->C;
-    C-->Effect;
-```
-
-This is the foundation on which _everything_ else is built.
-
-## Reactive Primitives
-
-### Overview
-
-The reactive system is built on the interaction between these two halves: **signals** and **effects**. When a signal is called inside an effect, the effect automatically subscribes to the signal. When a signal’s value is updated, it automatically notifies all its subscribers, and they re-run.
-
-The following simple example contains most of the core reactive concepts:
-
-```rust
-{{#include ../project/ch04_reactivity/src/main.rs}}
-```
-
-This creates a reactive graph like this:
-
-```mermaid
-graph TD;
-    count-->double_count;
-    count-->memoized_square;
-    count-->effect;
-    double_count-->effect;
-    memoized_square-->effect;
-```
-
-**Signals** are reactive values created using [`create_signal`](https://docs.rs/leptos/latest/leptos/fn.create_signal.html) or [`create_rw_signal`](https://docs.rs/leptos/latest/leptos/fn.create_rw_signal.html).
-
-**Derived Signals** computations in ordinary closures that rely on other signals. The computation re-runs whenever you access its value.
-
-**Memos** are computations that are memoized with [create_memo](https://docs.rs/leptos/latest/leptos/fn.create_memo.html). Memos only re-run when one of their signal dependencies has changed.
-
-And **effects** (created with [create_effect](<(https://docs.rs/leptos/latest/leptos/fn.create_effect.html)>) synchronize the reactive system with something outside it.
-
-The rest of this chapter will walk through each of these concepts in more depth.
-
-### Signals
-
-A **signal** is a piece of data that may change over time, and notifies other code when it has changed. This is the core primitive of Leptos’s reactive system.
-
-Creating a signal is very simple. You call `create_signal`, passing in the reactive scope and the default value, and receive a tuple containing a `ReadSignal` and a `WriteSignal`.
-
-```rust
-let (value, set_value) = create_signal(cx, 0);
-```
-
-> If you’ve used signals in Sycamore or Solid, observables in MobX or Knockout, or a similar primitive in reactive library, you probably have a pretty good idea of how signals work in Leptos. If you’re familiar with React, Yew, or Dioxus, you may recognize a similar pattern to their `use_state` hooks.
-
-#### `ReadSignal<T>`
-
-The [`ReadSignal`](https://docs.rs/leptos/latest/leptos/struct.ReadSignal.html) half of this tuple allows you to get the current value of the signal. Reading that value in a reactive context automatically subscribes to any further changes. You can access the value by simply calling the `ReadSignal` as a function.
-
-```rust
-let (value, set_value) = create_signal(cx, 0);
-
-// calling value() with return the current value of the signal,
-// and automatically track changes if you're in a reactive context
-assert_eq!(value(), 0);
-```
-
-> Here, a **reactive context** means anywhere within an `Effect`. Leptos’s templating system is built on top of its reactive system, so if you’re reading the signal’s value within the template, the template will automatically subscribe to the signal and update exactly the value that needs to change in the DOM.
-
-Calling a `ReadSignal` clones the value it contains. If that’s too expensive, use [`ReadSignal::with()`](https://docs.rs/leptos/latest/leptos/struct.ReadSignal.html#method.with) to borrow the value and do whatever you need.
-
-```rust
-struct MySuperExpensiveStruct {
-    a: String,
-    b: StructThatsSuperExpensiveToClone
-}
-let (value, set_value) = create_signal(cx, MySuperExpensiveStruct::default());
-
-// ❌ this is going to clone the `StructThatsSuperExpensiveToClone` unnecessarily!
-let lowercased = move || value().a.to_lowercase();
-// ✅ only use what we need
-let lowercased = move || value.with(|value: &MySuperExpensiveStruct| value.a.to_lowercase());
-```
-
-#### `WriteSignal<T>`
-
-The [`WriteSignal`](https://docs.rs/leptos/latest/leptos/struct.WriteSignal.html) half of this tuple allows you to update the value of the signal, which will automatically notify anything that’s listening to the value that something has changed. If you simply call the `WriteSignal` as a function, its value will be set to the argument you pass. If you want to mutate the value in place instead of replacing it, you can call [`WriteSignal::update`](https://docs.rs/leptos/latest/leptos/struct.WriteSignal.html#method.update) instead.
-
-```rust
-// often you just want to replace the value
-let (value, set_value) = create_signal(cx, 0);
-set_value(1);
-assert_eq!(value(), 1);
-
-// sometimes you want to mutate something in place, like a Vec. Just call update()
-let (items, set_items) = create_signal(cx, vec![0]);
-set_items.update(|items: &mut Vec<i32>| items.push(1));
-assert_eq!(items(), vec![1]);
-```
-
-> Under the hood, `set_value(1)` is just syntactic sugar for `set_value.update(|n| *n = 1)`.
-
-#### `RwSignal<T>`
-
-This kind of “read-write segregation,” in which the getter and the setter are stored in separate variables, may be familiar from the tuple-based ”hooks” pattern in libraries like React, Solid, Yew, or Dioxus. It encourages clear contracts between components. For example, if a child component only needs to be able to read a signal, but shouldn’t be able to update it (and therefore trigger changes in other parts of the application), you can pass it only the `ReadSignal`.
-
-Sometimes, however, you may prefer to keep the getter and setter combined in one variable. For example, it’s awkward and repetitive to store both halves of a signal in another data structure:
-
-```rust
-# use leptos::*;
-
-// pretty repetitive
-struct AppState {
-    count: ReadSignal<i32>,
-    set_count: WriteSignal<i32>,
-    name: ReadSignal<String>,
-    set_name: WriteSignal<String>
-}
-
-#[component]
-fn App(cx: Scope) {
-    let (count, set_count) = create_signal(cx, 0);
-    let (name, set_name) = create_signal(cx, "Alice".to_string());
-    provide_context(cx, AppState {
-        count,
-        set_count,
-        name,
-        set_name
-    })
-
-    todo!()
-}
-```
-
-Or maybe you just like to keep your getters and setters in one place.
-
-In this case, you can use [`create_rw_signal`](https://docs.rs/leptos/latest/leptos/fn.create_rw_signal.html) and the [`RwSignal`](https://docs.rs/leptos/latest/leptos/struct.RwSignal.html) type. This returns a **R**ead-**w**rite Signal, which has the same [`get`](https://docs.rs/leptos/latest/leptos/struct.RwSignal.html#method.get), [`with`](https://docs.rs/leptos/latest/leptos/struct.RwSignal.html#method.with), [`set`](https://docs.rs/leptos/latest/leptos/struct.RwSignal.html#method.set), and [`update`](https://docs.rs/leptos/latest/leptos/struct.RwSignal.html#method.update) functions as the `ReadSignal` and `WriteSignal` halves.
-
-```rust
-# use leptos::*;
-
-// better
-struct AppState {
-    count: RwSignal<i32>,
-    name: RwSignal<String>,
-}
-
-#[component]
-fn App(cx: Scope) {
-    let count = create_rw_signal(cx, 0);
-    let name = create_rw_signal(cx, "Alice".to_string());
-    provide_context(cx, AppState {
-        count,
-        name,
-    })
-
-    todo!()
-}
-```
-
-If you still want to hand off read-only access to another part of the app, you can get a `ReadSignal` with [`RwSignal::read_only()`](https://docs.rs/leptos/latest/leptos/struct.RwSignal.html#method.get).
-
-### Derived Signals
-
-(todo)
-
-### Memos
-
-(todo)
-
-### Effects
-
-(todo)

docs/book/src/SUMMARY.md

@@ -2,5 +2,40 @@
 
 - [Introduction](./01_introduction.md)
 - [Getting Started](./02_getting_started.md)
-- [Templating: Building User Interfaces](./03_building_ui.md)
-- [Reactivity: Making Things Interactive](./04_reactivity.md)
+- [Building User Interfaces](./view/README.md)
+  - [A Basic Component](./view/01_basic_component.md)
+  - [Dynamic Attributes](./view/02_dynamic_attributes.md)
+  - [Components and Props](./view/03_components.md)
+  - [Iteration](./view/04_iteration.md)
+  - [Forms and Inputs](./view/05_forms.md)
+  - [Control Flow](./view/06_control_flow.md)
+  - [Error Handling](./view/07_errors.md)
+  - [Parent-Child Communication](./view/08_parent_child.md)
+  - [Passing Children to Components](./view/09_component_children.md)
+- [Interlude: Reactivity and Functions](./interlude_functions.md)
+- [Testing](./testing.md)
+- [Async](./async/README.md)
+  - [Loading Data with Resources](./async/10_resources.md)
+  - [Suspense](./async/11_suspense.md)
+  - [Transition]()
+- [Interlude: Styling — CSS, Tailwind, Style.rs, and more]()
+- [State Management]()
+- [Interlude: Advanced Reactivity]()
+- [Router]()
+  - [Fundamentals]()
+  - [defining `<Routes/>`]()
+  - [`<A/>`]()
+  - [`<Form/>`]()
+- [Metadata]()
+- [SSR]()
+  - [Models of SSR]()
+  - [`cargo-leptos`]()
+  - [Hydration Footguns]()
+- [Request/Response]()
+  - [Headers]()
+  - [Cookies]()
+- [Server Functions]()
+  - [Actions]()
+  - [Forms]()
+  - [`<ActionForm/>`s]()
+  - [Turning off WebAssembly]()

docs/book/src/async/10_resources.md

@@ -0,0 +1,53 @@
+# Loading Data with Resources
+
+A [Resource](https://docs.rs/leptos/latest/leptos/struct.Resource.html) is a reactive data structure that reflects the current state of an asynchronous task, allowing you to integrate asynchronous `Future`s into the synchronous reactive system. Rather than waiting for its data to load with `.await`, you transform the `Future` into a signal that returns `Some(T)` if it has resolved, and `None` if it’s still pending.
+
+You do this by using the [`create_resource`](https://docs.rs/leptos/latest/leptos/fn.create_resource.html) function. This takes two arguments (other than the ubiquitous `cx`):
+
+1. a source signal, which will generate a new `Future` whenever it changes
+2. a fetcher function, which takes the data from that signal and returns a `Future`
+
+Here’s an example
+
+```rust
+// our source signal: some synchronous, local state
+let (count, set_count) = create_signal(cx, 0);
+
+// our resource
+let async_data = create_resource(cx,
+	count,
+	// every time `count` changes, this will run
+	|value| async move {
+		log!("loading data from API");
+		load_data(value).await
+	},
+);
+```
+
+To create a resource that simply runs once, you can pass a non-reactive, empty source signal:
+
+```rust
+let once = create_resource(cx, || (), |_| async move { load_data().await });
+```
+
+To access the value you can use `.read(cx)` or `.with(cx, |data| /* */)`. These work just like `.get()` and `.with()` on a signal—`read` clones the value and returns it, `with` applies a closure to it—but with two differences
+
+1. For any `Resource<_, T>`, they always return `Option<T>`, not `T`: because it’s always possible that your resource is still loading.
+2. They take a `Scope` argument. You’ll see why in the next chapter, on `<Suspense/>`.
+
+So, you can show the current state of a resource in your view:
+
+```rust
+let once = create_resource(cx, || (), |_| async move { load_data().await });
+view! { cx,
+	<h1>"My Data"</h1>
+	{move || match once.read(cx) {
+		None => view! { cx, <p>"Loading..."</p> }.into_view(cx),
+		Some(data) => view! { cx, <ShowData data/> }.into_view(cx)
+	}}
+}
+```
+
+Resources also provide a `refetch()` method that allow you to manually reload the data (for example, in response to a button click) and a `loading()` method that returns a `ReadSignal<bool>` indicating whether the resource is currently loading or not.
+
+<iframe src="https://codesandbox.io/p/sandbox/10-async-resources-4z0qt3?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A3%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A3%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/async/11_suspense.md

@@ -0,0 +1,72 @@
+# `<Suspense/>`
+
+In the previous chapter, we showed how you can create a simple loading screen to show some fallback while a resource is loading.
+
+```rust
+let (count, set_count) = create_signal(cx, 0);
+let a = create_resource(cx, count, |count| async move { load_a(count).await });
+
+view! { cx,
+	<h1>"My Data"</h1>
+	{move || match once.read(cx) {
+		None => view! { cx, <p>"Loading..."</p> }.into_view(cx),
+		Some(data) => view! { cx, <ShowData data/> }.into_view(cx)
+	}}
+}
+```
+
+But what if we have two resources, and want to wait for both of them?
+
+```rust
+let (count, set_count) = create_signal(cx, 0);
+let (count2, set_count2) = create_signal(cx, 0);
+let a = create_resource(cx, count, |count| async move { load_a(count).await });
+let b = create_resource(cx, count2, |count| async move { load_b(count).await });
+
+view! { cx,
+	<h1>"My Data"</h1>
+	{move || match (a.read(cx), b.read(cx)) {
+		_ => view! { cx, <p>"Loading..."</p> }.into_view(cx),
+		(Some(a), Some(b)) => view! { cx,
+			<ShowA a/>
+			<ShowA b/>
+		}.into_view(cx)
+	}}
+}
+```
+
+That’s not _so_ bad, but it’s kind of annoying. What if we could invert the flow of control?
+
+The [`<Suspense/>`](https://docs.rs/leptos/latest/leptos/fn.Suspense.html) component lets us do exactly that. You give it a `fallback` prop and children, one or more of which usually involves reading from a resource. Reading from a resource “under” a `<Suspense/>` (i.e., in one of its children) registers that resource with the `<Suspense/>`. If it’s still waiting for resources to load, it shows the `fallback`. When they’ve all loaded, it shows the children.
+
+```rust
+let (count, set_count) = create_signal(cx, 0);
+let (count2, set_count2) = create_signal(cx, 0);
+let a = create_resource(cx, count, |count| async move { load_a(count).await });
+let b = create_resource(cx, count2, |count| async move { load_b(count).await });
+
+view! { cx,
+	<h1>"My Data"</h1>
+	<Suspense
+		fallback=move || view! { cx, <p>"Loading..."</p> }
+	>
+		<h2>"My Data"</h2>
+		<h3>"A"</h3>
+		{move || {
+			a.read(cx)
+				.map(|a| view! { cx, <ShowA a/> })
+		}}
+		<h3>"B"</h3>
+		{move || {
+			b.read(cx)
+				.map(|b| view! { cx, <ShowB b/> })
+		}}
+	</Suspense>
+}
+```
+
+Every time one of the resources is reloading, the `"Loading..."` fallback will show again.
+
+This inversion of the flow of control makes it easier to add or remove individual resources, as you don’t need to handle the matching yourself. It also unlocks some massive performance improvements during server-side rendering, which we’ll talk about during a later chapter.
+
+<iframe src="https://codesandbox.io/p/sandbox/10-async-resources-4z0qt3?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A3%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A3%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/async/12_transition.md

@@ -0,0 +1,9 @@
+# `<Transition/>`
+
+You’ll notice in the `<Suspense/>` example that if you keep reloading the data, it keeps flickering back to `"Loading..."`. Sometimes this is fine. For other times, there’s [`<Transition/>`](https://docs.rs/leptos/latest/leptos/fn.Suspense.html).
+
+`<Transition/>` behaves exactly the same as `<Suspense/>`, but instead of falling back every time, it only shows the fallback the first time. On all subsequent loads, it continues showing the old data until the new data are ready. This can be really handy to prevent the flickering effect, and to allow users to continue interacting with your application.
+
+This example shows how you can create a simple tabbed contact list with `<Transition/>`. When you select a new tab, it continues showing the current contact until the new data laods. This can be a much better user experience than constantly falling back to a loading message.
+
+<iframe src="https://codesandbox.io/p/sandbox/12-transition-sn38sd?selection=%5B%7B%22endColumn%22%3A15%2C%22endLineNumber%22%3A2%2C%22startColumn%22%3A15%2C%22startLineNumber%22%3A2%7D%5D&file=%2Fsrc%2Fmain.rs" width="100%" height="1000px"></iframe>

docs/book/src/async/README.md

@@ -0,0 +1,9 @@
+# Working with `async`
+
+So far we’ve only been working with synchronous users interfaces: You provide some input,
+the app immediately process it and updates the interface. This is great, but is a tiny
+subset of what web applications do. In particular, most web apps have to deal with some kind
+of asynchronous data loading, usually loading something from an API.
+
+Asynchronous data is notoriously hard to integrate with the synchronous parts of your code.
+In this chapter, we’ll see how Leptos helps smooth out that process for you.

docs/book/src/interlude_functions.md

@@ -0,0 +1,76 @@
+# Interlude: Reactivity and Functions
+
+One of our core contributors said to me recently: “I never used closures this often
+until I started using Leptos.” And it’s true. Closures are at the heart of any Leptos
+application. It sometimes looks a little silly:
+
+```rust
+// a signal holds a value, and can be updated
+let (count, set_count) = create_signal(cx, 0);
+
+// a derived signal is a function that accesses other signals
+let double_count = move || count() * 2;
+let count_is_odd = move || count() & 1 == 1;
+let text = move || if count_is_odd() {
+	"odd"
+} else {
+	"even"
+};
+
+// an effect automatically tracks the signals it depends on
+// and re-runs when they change
+create_effect(cx, move |_| {
+	log!("text = {}", text());
+});
+
+view! { cx,
+	<p>{move || text().to_uppercase()}</p>
+}
+```
+
+Closures, closures everywhere!
+
+But why?
+
+## Functions and UI Frameworks
+
+Functions are at the heart of every UI framework. And this makes perfect sense. Creating a user interface is basically divided into two phases:
+
+1. initial rendering
+2. updates
+
+In a web framework, the framework does some kind of initial rendering. Then it hands control back over to the browser. When certain events fire (like a mouse click) or asynchronous tasks finish (like an HTTP request finishing), the browser wakes the framework back up to update something. The framework runs some kind of code to update your user interface, and goes back asleep until the browser wakes it up again.
+
+The key phrase here is “runs some kind of code.” The natural way to “run some kind of code” at an arbitrary point in time—in Rust or in any other programming language—is to call a function. And in fact every UI framework is based on rerunning some kind of function over and over:
+
+1. virtual DOM (VDOM) frameworks like React, Yew, or Dioxus rerun a component or render function over and over, to generate a virtual DOM tree that can be reconciled with the previous result to patch the DOM
+2. compiled frameworks like Angular and Svelte divide your component templates into “create” and “update” functions, rerunning the update function when they detect a change to the component’s state
+3. in fine-grained reactive frameworks like SolidJS, Sycamore, or Leptos, _you_ define the functions that re-run
+
+That’s what all our components are doing.
+
+Take our typical `<SimpleCounter/>` example in its simplest form:
+
+```rust
+#[component]
+pub fn SimpleCounter(cx: Scope) -> impl IntoView {
+    let (value, set_value) = create_signal(cx, 0);
+
+    let increment = move |_| set_value.update(|value| *value += 1);
+
+    view! { cx,
+		<button on:click=increment>
+			{value}
+		</button>
+    }
+}
+```
+
+The `SimpleCounter` function itself runs once. The `value` signal is created once. The framework hands off the `increment` function to the browser as an event listener. When you click the button, the browser calls `increment`, which updates `value` via `set_value`. And that updates the single text node represented in our view by `{value}`.
+
+Closures are key to reactivity. They provide the framework with the ability to re-run the smallest possible unit of your application in responsive to a change.
+
+So remember two things:
+
+1. Your component function is a setup function, not a render function: it only runs once.
+2. For values in your view template to be reactive, they must be functions: either signals (which implement the `Fn` traits) or closures.

docs/book/src/testing.md

@@ -0,0 +1,180 @@
+# Testing Your Components
+
+Testing user interfaces can be relatively tricky, but really important. This article
+will discuss a couple principles and approaches for testing a Leptos app.
+
+## 1. Test business logic with ordinary Rust tests
+
+In many cases, it makes sense to pull the logic out of your components and test
+it separately. For some simple components, there’s no particular logic to test, but
+for many it’s worth using a testable wrapping type and implementing the logic in
+ordinary Rust `impl` blocks.
+
+For example, instead of embedding logic in a component directly like this:
+
+```rust
+#[component]
+pub fn TodoApp(cx: Scope) -> impl IntoView {
+	let (todos, set_todos) = create_signal(cx, vec![Todo { /* ... */ }]);
+	// ⚠️ this is hard to test because it's embedded in the component
+	let maximum = move || todos.with(|todos| {
+		todos.iter().filter(|todo| todo.completed).sum()
+	});
+}
+```
+
+You could pull that logic out into a separate data structure and test it:
+
+```rust
+pub struct Todos(Vec<Todo>);
+
+impl Todos {
+	pub fn remaining(&self) -> usize {
+		todos.iter().filter(|todo| todo.completed).sum()
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	#[test]
+	fn test_remaining {
+		// ...
+	}
+}
+
+#[component]
+pub fn TodoApp(cx: Scope) -> impl IntoView {
+	let (todos, set_todos) = create_signal(cx, Todos(vec![Todo { /* ... */ }]));
+	// ✅ this has a test associated with it
+	let maximum = move || todos.with(Todos::remaining);
+}
+```
+
+In general, the less of your logic is wrapped into your components themselves, the
+more idiomatic your code will feel and the easier it will be to test.
+
+## 2. Test components with `wasm-bindgen-test`
+
+[`wasm-bindgen-test`](https://crates.io/crates/wasm-bindgen-test) is a great utility
+for integrating or end-to-end testing WebAssembly apps in a headless browser.
+
+To use this testing utility, you need to add `wasm-bindgen-test` to your `Cargo.toml`:
+
+```toml
+[dev-dependencies]
+wasm-bindgen-test = "0.3.0"
+```
+
+You should create tests in a separate `tests` directory. You can then run your tests in the browser of your choice:
+
+```bash
+wasm-pack test --firefox
+```
+
+> To see the full setup, check out the tests for the [`counter`](https://github.com/leptos-rs/leptos/tree/main/examples/counter) example.
+
+### Writing Your Tests
+
+Most tests will involve some combination of vanilla DOM manipulation and comparison to a `view`. For example, here’s a test [for the
+`counter` example](https://github.com/leptos-rs/leptos/blob/main/examples/counter/tests/mod.rs).
+
+First, we set up the testing environment.
+
+```rust
+use wasm_bindgen_test::*;
+use counter::*;
+use leptos::*;
+use web_sys::HtmlElement;
+
+// tell the test runner to run tests in the browser
+wasm_bindgen_test_configure!(run_in_browser);
+```
+
+I’m going to create a simpler wrapper for each test case, and mount it there.
+This makes it easy to encapsulate the test results.
+
+```rust
+// like marking a regular test with #[test]
+#[wasm_bindgen_test]
+fn clear() {
+    let document = leptos::document();
+    let test_wrapper = document.create_element("section").unwrap();
+    document.body().unwrap().append_child(&test_wrapper);
+
+    // start by rendering our counter and mounting it to the DOM
+    // note that we start at the initial value of 10
+    mount_to(
+        test_wrapper.clone().unchecked_into(),
+        |cx| view! { cx, <SimpleCounter initial_value=10 step=1/> },
+    );
+```
+
+We’ll use some manual DOM operations to grab the `<div>` that wraps
+the whole component, as well as the `clear` button.
+
+```rust
+    // now we extract the buttons by iterating over the DOM
+    // this would be easier if they had IDs
+    let div = test_wrapper.query_selector("div").unwrap().unwrap();
+    let clear = test_wrapper
+        .query_selector("button")
+        .unwrap()
+        .unwrap()
+        .unchecked_into::<web_sys::HtmlElement>();
+```
+
+Now we can use ordinary DOM APIs to simulate user interaction.
+
+```rust
+    // now let's click the `clear` button
+    clear.click();
+```
+
+You can test individual DOM element attributes or text node values. Sometimes
+I like to test the whole view at once. We can do this by testing the element’s
+`outerHTML` against our expectations.
+
+```rust
+    assert_eq!(
+        div.outer_html(),
+        // here we spawn a mini reactive system to render the test case
+        run_scope(create_runtime(), |cx| {
+            // it's as if we're creating it with a value of 0, right?
+            let (value, set_value) = create_signal(cx, 0);
+
+            // we can remove the event listeners because they're not rendered to HTML
+            view! { cx,
+                <div>
+                    <button>"Clear"</button>
+                    <button>"-1"</button>
+                    <span>"Value: " {value} "!"</span>
+                    <button>"+1"</button>
+                </div>
+            }
+            // the view returned an HtmlElement<Div>, which is a smart pointer for
+            // a DOM element. So we can still just call .outer_html()
+            .outer_html()
+        })
+    );
+```
+
+That test involved us manually replicating the `view` that’s inside the component.
+There's actually an easier way to do this... We can just test against a `<SimpleCounter/>`
+with the initial value `0`. This is where our wrapping element comes in: I’ll just test
+the wrapper’s `innerHTML` against another comparison case.
+
+```rust
+    assert_eq!(test_wrapper.inner_html(), {
+        let comparison_wrapper = document.create_element("section").unwrap();
+        leptos::mount_to(
+            comparison_wrapper.clone().unchecked_into(),
+            |cx| view! { cx, <SimpleCounter initial_value=0 step=1/>},
+        );
+        comparison_wrapper.inner_html()
+    });
+}
+```
+
+This is only a very limited introduction to testing. But I hope it’s useful as you begin to build applications.
+
+> For more, see [the testing section of the `wasm-bindgen` guide](https://rustwasm.github.io/wasm-bindgen/wasm-bindgen-test/index.html#testing-on-wasm32-unknown-unknown-with-wasm-bindgen-test).

docs/book/src/view/01_basic_component.md

@@ -0,0 +1,143 @@
+# A Basic Component
+
+That “Hello, world!” was a *very* simple example. Let’s move on to something a
+little more like an ordinary app.
+
+First, let’s edit the `main` function so that, instead of rendering the whole
+app, it just renders an `<App/>` component. Components are the basic unit of
+composition and design in most web frameworks, and Leptos is no exception. 
+Conceptually, they are similar to HTML elements: they represent a section of the 
+DOM, with self-contained, defined behavior. Unlike HTML elements, they are in 
+`PascalCase`, so most Leptos applications will start with something like an 
+`<App/>` component.
+
+```rust
+fn main() {
+    leptos::mount_to_body(|cx| view! { cx, <App/> })
+}
+```
+
+Now let’s define our `<App/>` component itself. Because it’s relatively simple,
+I’ll give you the whole thing up front, then walk through it line by line.
+
+```rust
+#[component]
+fn App(cx: Scope) -> impl IntoView {
+    let (count, set_count) = create_signal(cx, 0);
+
+    view! { cx,
+        <button
+            on:click=move |_| {
+                set_count.update(|n| *n += 1);
+            }
+        >
+            "Click me"
+            {move || count.get()}
+        </button>
+    }
+}
+```
+
+## The Component Signature
+```rust
+#[component]
+```
+
+Like all component definitions, this begins with the [`#[component]`](https://docs.rs/leptos/latest/leptos/attr.component.html) macro. `#[component]` annotates a function so it can be 
+used as a component in your Leptos application. We’ll see some of the other features of
+this macro in a couple chapters.
+
+```rust
+fn App(cx: Scope) -> impl IntoView
+```
+
+Every component is a function with the following characteristics
+1. It takes a reactive [`Scope`](https://docs.rs/leptos/latest/leptos/struct.Scope.html)
+   as its first argument. This `Scope` is our entrypoint into the reactive system.
+   By convention, it’s usually named `cx`.
+2. You can include other arguments, which will be available as component “props.”
+3. Component functions return `impl IntoView`, which is an opaque type that includes
+   anything you could return from a Leptos `view`.
+
+## The Component Body
+The body of the component function is a set-up function that runs once, not a 
+render function that re-runs multiple times. You’ll typically use it to create a
+few reactive variables, define any side effects that run in response to those values
+changing, and describe the user interface.
+
+```rust
+let (count, set_count) = create_signal(cx, 0);
+```
+[`create_signal`](https://docs.rs/leptos/latest/leptos/fn.create_signal.html)
+creates a signal, the basic unit of reactive change and state management in Leptos.
+This returns a `(getter, setter)` tuple. To access the current value, you’ll 
+use `count.get()` (or, on `nightly` Rust, the shorthand `count()`). To set the 
+current value, you’ll call `set_count.set(...)` (or `set_count(...)`).
+
+> `.get()` clones the value and `.set()` overwrites it. In many cases, it’s more 
+efficient to use `.with()` or `.update()`; check out the docs for [`ReadSignal`](https://docs.rs/leptos/latest/leptos/struct.ReadSignal.html) and [`WriteSignal`](https://docs.rs/leptos/latest/leptos/struct.WriteSignal.html) if you’d like to learn more about those trade-offs at this point.
+
+## The View 
+
+Leptos defines user interfaces using a JSX-like format via the [`view`](https://docs.rs/leptos/latest/leptos/macro.view.html) macro.
+
+```rust
+view! { cx,
+    <button
+        // define an event listener with on:
+        on:click=move |_| {
+            set_count.update(|n| *n += 1);
+        }
+    >
+        // text nodes are wrapped in quotation marks
+        "Click me: "
+        // blocks can include Rust code
+        {move || count.get()}
+    </button>
+}
+```
+
+This should mostly be easy to understand: it looks like HTML, with a special
+`on:click` to define a `click` event listener, a text node that’s formatted like
+a Rust string, and then...
+```rust
+{move || count.get()}
+```
+whatever that is.
+
+People sometimes joke that they use more closures in their first Leptos application 
+than they’ve ever used in their lives. And fair enough. Basically, passing a function 
+into the view tells the framework: “Hey, this is something that might change.”
+
+When we click the button and call `set_count`, the `count` signal is updated. This 
+`move || count.get()` closure, whose value depends on the value of `count`, re-runs, 
+and the framework makes a targeted update to that one specific text node, touching 
+nothing else in your application. This is what allows for extremely efficient updates
+to the DOM.
+
+Now, if you have Clippy on—or if you have a particularly sharp eye—you might notice
+that this closure is redundant, at least if you’re in `nightly` Rust. If you’re using 
+Leptos with `nightly` Rust, signals are already functions, so the closure is unnecessary.
+As a result, you can write a simpler view: 
+```rust
+view! { cx,
+    <button /* ... */>
+        "Click me: "
+        // identical to {move || count.get()}
+        {count}
+    </button>
+}
+```
+
+Remember—and this is *very important*—only functions are reactive. This means that 
+`{count}` and `{count()}` do very different things in your view. `{count}` passes 
+in a function, telling the framework to update the view every time `count` changes.
+`{count()}` access the value of `count` once, and passes an `i32` into the view, 
+rendering it once, unreactively. You can see the difference in the CodeSandbox below!
+
+> Throughout this tutorial, we’ll use CodeSandbox to show interactive examples. To 
+show the browser in the sandbox, you may need to click `Add DevTools >
+Other Previews > 8080.` Hover over any of the variables to show Rust-Analyzer details 
+and docs for what’s going on. Feel free to fork the examples to play with them yourself!
+
+<iframe src="https://codesandbox.io/p/sandbox/1-basic-component-3d74p3?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A31%2C%22endLineNumber%22%3A19%2C%22startColumn%22%3A31%2C%22startLineNumber%22%3A19%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/02_dynamic_attributes.md

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+# `view`: Dynamic Attributes and Classes
+
+So far we’ve seen how to use the `view` macro to create event listeners and to 
+create dynamic text by passing a function (such as a signal) into the view.
+
+But of course there are other things you might want to update in your user interface.
+In this section, we’ll look at how to update attributes and classes dynamically, 
+and we’ll introduce the concept of a **derived signal**.
+
+Let’s start with a simple component that should be familiar: click a button to 
+increment a counter.
+
+```rust
+#[component]
+fn App(cx: Scope) -> impl IntoView {
+    let (count, set_count) = create_signal(cx, 0);
+
+    view! { cx,
+        <button
+            on:click=move |_| {
+                set_count.update(|n| *n += 1);
+            }
+```
+
+So far, this is just the example from the last chapter.
+
+## Dynamic Classes
+
+Now let’s say I’d like to update the list of CSS classes on this element dynamically.
+For example, let’s say I want to add the class `red` when the count is odd. I can
+do this using the `class:` syntax. 
+```rust
+class:red=move || count() & 1 == 1
+```
+`class:` attributes take
+1. the class name, following the colon (`red`)
+2. a value, which can be a `bool` or a function that returns a `bool`
+
+When the value is `true`, the class is added. When the value is `false`, the class
+is removed. And if the value is a function that accesses a signal, the class will 
+reactively update when the signal changes.
+
+Now every time I click the button, the text should toggle between red and black as 
+the number switches between even and odd.
+
+## Dynamic Attributes
+
+The same applies to plain attributes. Passing a plain string or primitive value to
+an attribute gives it a static value. Passing a function (including a signal) to
+an attribute causes it to update its value reactively. Let’s add another element 
+to our view:
+```rust
+<progress
+    max="50"
+    // signals are functions, so this <=> `move || count.get()`
+    value=count
+/>
+```
+
+Now every time we set the count, not only will the `class` of the `<button>` be 
+toggled, but the `value` of the `<progress>` bar will increase, which means that 
+our progress bar will move forward.
+
+## Derived Signals 
+
+Let’s go one layer deeper, just for fun.
+
+You already know that we create reactive interfaces just by passing functions into 
+the `view`. This means that we can easily change our progress bar. For example,
+suppose we want it to move twice as fast:
+```rust
+<progress
+    max="50"
+    value=move || count() * 2
+/>
+```
+
+But imagine we want to reuse that calculation in more than one place. You can do this
+using a **derived signal**: a closure that accesses a signal.
+```rust
+let double_count = move || count() * 2;
+
+/* insert the rest of the view */ 
+<progress
+    max="50"
+    // we use it once here
+    value=double_count
+/>
+<p>
+    "Double Count: " 
+    // and again here
+    {double_count}
+</p>
+```
+
+Derived signals let you create reactive computed values that can be used in multiple 
+places in your application with minimal overhead.
+
+> Note: Using a derived signal like this means that the calculation runs once per 
+signal change per place we access `double_count`; in other words, twice. This is a
+very cheap calculation, so that’s fine. We’ll look at memos in a later chapter, which 
+are designed to solve this problem for expensive calculations.
+
+<iframe src="https://codesandbox.io/p/sandbox/2-dynamic-attribute-pqyvzl?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A2%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A2%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/03_components.md

@@ -0,0 +1,317 @@
+# Components and Props
+
+So far, we’ve been building our whole application in a single component. This 
+is fine for really tiny examples, but in any real application you’ll need to 
+break the user interface out into multiple components, so you can break your 
+interface down into smaller, reusable, composable chunks.
+
+Let’s take our progress bar example. Imagine that you want two progress bars 
+instead of one: one that advances one tick per click, one that advances two ticks
+per click.
+
+You _could_ do this by just creating two `<progress>` elements:
+
+```rust
+let (count, set_count) = create_signal(cx, 0);
+let double_count = move || count() * 2;
+
+view! { 
+    <progress
+        max="50"
+        value=progress
+    />
+    <progress
+        max="50"
+        value=double_count
+    />
+```
+
+But of course, this doesn’t scale very well. If you want to add a third progress
+bar, you need to add this code another time. And if you want to edit anything 
+about it, you need to edit it in triplicate.
+
+Instead, let’s create a `<ProgressBar/>` component.
+
+```rust
+#[component]
+fn ProgressBar(
+    cx: Scope
+) -> impl IntoView {
+    view! { cx,
+        <progress
+            max="50"
+            // hmm... where will we get this from?
+            value=progress
+        />
+    }
+}
+```
+
+There’s just one problem: `progress` is not defined. Where should it come from? 
+When we were defining everything manually, we just used the local variable names. 
+Now we need some way to pass an argument into the component.
+
+## Component Props 
+
+We do this using component properties, or “props.” If you’ve used another frontend
+framework, this is probably a familiar idea. Basically, properties are to components 
+as attributes are to HTML elements: they let you pass additional information into 
+the component.
+
+In Leptos, you define props by giving additional arguments to the component function.
+
+```rust
+#[component]
+fn ProgressBar(
+    cx: Scope,
+    progress: ReadSignal<i32>
+) -> impl IntoView {
+    view! { cx,
+        <progress
+            max="50"
+            // now this works 
+            value=progress
+        />
+    }
+}
+```
+
+Now we can use our component in the main `<App/>` component’s view.
+
+```rust
+#[component]
+fn App(cx: Scope) -> impl IntoView {
+    let (count, set_count) = create_signal(cx, 0);
+    view! { cx,
+        <button on:click=move |_| { set_count.update(|n| *n += 1); }>
+            "Click me"
+        </button>
+        // now we use our component!
+        <ProgressBar progress=count/>
+    }
+}
+```
+
+Using a component in the view looks a lot like using an HTML element. You’ll 
+notice that you can easily tell the difference between an element and a component 
+because components always have `PascalCase` names. You pass the `progress` prop 
+in as if it were an HTML element attribute. Simple.
+
+> ### Important Note 
+> For every `Component`, Leptos generates a corresponding `ComponentProps` type. This 
+is what allows us to have named props, when Rust does not have named function parameters.
+If you’re defining a component in one module and importing it into another, make 
+sure you include this `ComponentProps` type:
+>
+> `use progress_bar::{ProgressBar, ProgressBarProps};`
+
+### Reactive and Static Props
+
+You’ll notice that throughout this example, `progress` takes a reactive 
+`ReadSignal<i32>`, and not a plain `i32`. This is **very important**.
+
+Component props have no special meaning attached to them. A component is simply 
+a function that runs once to set up the user interface. The only way to tell the 
+interface to respond to changing is to pass it a signal type. So if you have a 
+component property that will change over time, like our `progress`, it should 
+be a signal.
+
+### `optional` Props 
+
+Right now the `max` setting is hard-coded. Let’s take that as a prop too. But 
+let’s add a catch: let’s make this prop optional by annotating the particular 
+argument to the component function with `#[prop(optional)]`.
+
+```rust
+#[component]
+fn ProgressBar(
+    cx: Scope,
+    // mark this prop optional 
+    // you can specify it or not when you use <ProgressBar/>
+    #[prop(optional)]
+    max: u16,
+    progress: ReadSignal<i32>
+) -> impl IntoView {
+    view! { cx,
+        <progress
+            max=max
+            value=progress
+        />
+    }
+}
+```
+
+Now, we can use `<ProgressBar max=50 value=count/>`, or we can omit `max`
+to use the default value (i.e., `<ProgressBar value=count/>`). The default value 
+on an `optional` is its `Default::default()` value, which for a `u16` is going to
+be `0`. In the case of a progress bar, a max value of `0` is not very useful.
+
+So let’s give it a particular default value instead.
+
+### `default` props
+
+You can specify a default value other than `Default::default()` pretty simply
+with `#[prop(default = ...)`.
+
+```rust
+#[component]
+fn ProgressBar(
+    cx: Scope,
+    #[prop(default = 100)]
+    max: u16,
+    progress: ReadSignal<i32>
+) -> impl IntoView {
+    view! { cx,
+        <progress
+            max=max
+            value=progress
+        />
+    }
+}
+```
+
+### Generic Props
+
+This is great. But we began with two counters, one driven by `count`, and one by
+the derived signal `double_count`. Let’s recreate that by using `double_count`
+as the `progress` prop on another `<ProgressBar/>`.
+
+```rust
+#[component]
+fn App(cx: Scope) -> impl IntoView {
+    let (count, set_count) = create_signal(cx, 0);
+    let double_count = move || count() * 2;
+
+    view! { cx,
+        <button on:click=move |_| { set_count.update(|n| *n += 1); }>
+            "Click me"
+        </button>
+        <ProgressBar progress=count/>
+        // add a second progress bar 
+        <ProgressBar progress=double_count/>
+    }
+}
+```
+
+Hm... this won’t compile. It should be pretty easy to understand why: we’ve declared
+that the `progress` prop takes `ReadSignal<i32>`, and `double_count` is not 
+`ReadSignal<i32>`. As rust-analyzer will tell you, its type is `|| -> i32`, i.e., 
+it’s a closure that returns an `i32`.
+
+There are a couple ways to handle this. One would be to say: “Well, I know that 
+a `ReadSignal` is a function, and I know that a closure is a function; maybe I 
+could just take any function?” If you’re savvy, you may know that both these 
+implement the trait `Fn() -> i32`. So you could use a generic component:
+
+```rust
+#[component]
+fn ProgressBar<F>(
+    cx: Scope,
+    #[prop(default = 100)]
+    max: u16,
+    progress: F
+) -> impl IntoView 
+where 
+    F: Fn() -> i32
+{
+    view! { cx,
+        <progress
+            max=max
+            value=progress
+        />
+    }
+}
+```
+
+This is a perfectly reasonable way to write this component: `progress` now takes 
+any value that implements this `Fn()` trait.
+
+> Note that generic component props _cannot_ be specified inline (as `<F: Fn() -> i32>`)
+or as `progress: impl Fn() -> i32`, in part because they’re actually used to generate 
+a `struct ProgressBarProps`, and struct fields cannot be `impl` types.
+
+### `into` Props 
+
+There’s one more way we could implement this, and it would be to use `#[prop(into)]`. 
+This attribute automatically calls `.into()` on the values you pass as proprs,
+which allows you to pass props of different values easily.
+
+In this case, it’s helpful to know about the 
+[`Signal`](https://docs.rs/leptos/latest/leptos/struct.Signal.html) type. `Signal`
+is a enumerated type that represents any kind of readable reactive signal. It can 
+be useful when defining APIs for components you’ll want to reuse while passing 
+different sorts of signals. The [`MaybeSignal`](https://docs.rs/leptos/latest/leptos/enum.MaybeSignal.html) type is useful when you want to be able to take either a static or 
+reactive value.
+
+
+```rust
+#[component]
+fn ProgressBar(
+    cx: Scope,
+    #[prop(default = 100)]
+    max: u16,
+    #[prop(into)]
+    progress: Signal<i32>
+) -> impl IntoView 
+{
+    view! { cx,
+        <progress
+            max=max
+            value=progress
+        />
+    }
+}
+
+#[component]
+fn App(cx: Scope) -> impl IntoView {
+    let (count, set_count) = create_signal(cx, 0);
+    let double_count = move || count() * 2;
+
+    view! { cx,
+        <button on:click=move |_| { set_count.update(|n| *n += 1); }>
+            "Click me"
+        </button>
+        // .into() converts `ReadSignal` to `Signal`
+        <ProgressBar progress=count/>
+        // use `Signal::derive()` to wrap a derived signal
+        <ProgressBar progress=Signal::derive(cx, double_count)/>
+    }
+}
+```
+
+## Documenting Components
+
+This is one of the least essential but most important sections of this book. 
+It’s not strictly necessary to document your components and their props. It may 
+be very important, depending on the size of your team and your app. But it’s very 
+easy, and bears immediate fruit.
+
+To document a component and its props, you can simply add doc comments on the 
+component function, and each one of the props:
+
+```rust
+/// Shows progress toward a goal.
+#[component]
+fn ProgressBar(
+    cx: Scope,
+    /// The maximum value of the progress bar.
+    #[prop(default = 100)]
+    max: u16,
+    /// How much progress should be displayed.
+    #[prop(into)]
+    progress: Signal<i32>,
+) -> impl IntoView {
+    /* ... */
+}
+```
+
+That’s all you need to do. These behave like ordinary Rust doc comments, except
+that you can document individual component props, which can’t be done with Rust
+function arguments.
+
+This will automatically generate documentation for your component, its `Props` 
+type, and each of the fields used to add props. It can be a little hard to 
+understand how powerful this is until you hover over the component name or props 
+and see the power of the `#[component]` macro combined with rust-analyzer here.
+
+<iframe src="https://codesandbox.io/p/sandbox/3-components-50t2e7?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A7%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A7%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/04_iteration.md

@@ -0,0 +1,88 @@
+# Iteration
+
+Whether you’re listing todos, displaying a table, or showing product images, 
+iterating over a list of items is a common task in web applications. Reconciling
+the differences between changing sets of items can also be one of the trickiest
+tasks for a framework to handle well.
+
+Leptos supports to two different patterns for iterating over items:
+1. For static views: `Vec<_>`
+2. For dynamic lists: `<For/>`
+
+## Static Views with `Vec<_>`
+
+Sometimes you need to show an item repeatedly, but the list you’re drawing from 
+does not often change. In this case, it’s important to know that you can insert 
+any `Vec<IV> where IV: IntoView` into your view. In other views, if you can render
+`T`, you can render `Vec<T>`.
+
+```rust
+let values = vec![0, 1, 2];
+view! { cx,
+    // this will just render "012"
+    <p>{values.clone()}</p>
+    // or we can wrap them in <li>
+    <ul>
+        {values.into_iter()
+            .map(|n| view! { cx, <li>{n}</li>})
+            .collect::<Vec<_>>()}
+    </ul>
+}
+```
+
+The fact that the _list_ is static doesn’t mean the interface needs to be static.
+You can render dynamic items as part of a static list.
+
+```rust
+// create a list of N signals
+let counters = (1..=length).map(|idx| create_signal(cx, idx));
+
+// each item manages a reactive view
+// but the list itself will never change
+let counter_buttons = counters
+    .map(|(count, set_count)| {
+        view! { cx,
+            <li>
+                <button
+                    on:click=move |_| set_count.update(|n| *n += 1)
+                >
+                    {count}
+                </button>
+            </li>
+        }
+    })
+    .collect::<Vec<_>>();
+
+view! { cx,
+    <ul>{counter_buttons}</ul>
+}
+```
+
+You _can_ render a `Fn() -> Vec<_>` reactively as well. But note that every time 
+it changes, this will rerender every item in the list. This is quite inefficient!
+Fortunately, there’s a better way.
+
+## Dynamic Rendering with the `<For/>` Component
+
+The [`<For/>`](https://docs.rs/leptos/latest/leptos/fn.For.html) component is a 
+keyed dynamic list. It takes three props:
+- `each`: a function (such as a signal) that returns the items `T` to be iterated over
+- `key`: a key function that takes `&T` and returns a stable, unique key or ID
+- `view`: renders each `T` into a view 
+
+`key` is, well, the key. You can add, remove, and move items within the list. As
+long as each item’s key is stable over time, the framework does not need to rerender
+any of the items, unless they are new additions, and it can very efficiently add,
+remove, and move items as they change. This allows for extremely efficient updates 
+to the list as it changes, with minimal additional work.
+
+Creating a good `key` can be a little tricky. You generally do _not_ want to use 
+an index for this purpose, as it is not stable—if you remove or move items, their 
+indices change.
+
+But it’s a great idea to do something like generating a unique ID for each row as 
+it is generated, and using that as an ID for the key function.
+
+Check out the `<DynamicList/>` component below for an example.
+
+<iframe src="https://codesandbox.io/p/sandbox/4-iteration-sglt1o?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A6%2C%22endLineNumber%22%3A55%2C%22startColumn%22%3A5%2C%22startLineNumber%22%3A31%7D%5D" width="100%" height="100px"></iframe>

docs/book/src/view/05_forms.md

@@ -0,0 +1,107 @@
+# Forms and Inputs
+
+Forms and form inputs are an important part of interactive apps. There are two 
+basic patterns for interacting with inputs in Leptos, which you may recognize
+if you’re familiar with React, SolidJS, or a similar framework: using **controlled**
+or **uncontrolled** inputs.
+
+## Controlled Inputs
+
+In a "controlled input," the framework controls the state of the input 
+element. On every `input` event, it updates a local signal that holds the current 
+state, which in turn updates the `value` prop of the input.
+
+There are two important things to remember:
+1. The `input` event fires on (almost) every change to the element, while the 
+   `change` event fires (more or less) when you unfocus the input. You probably 
+   want `on:input`, but we give you the freedom to choose.
+2. The `value` *attribute* only sets the initial value of the input, i.e., it 
+   only updates the input up to the point that you begin typing. The `value` 
+   *property* continues updating the input after that. You usually want to set 
+   `prop:value` for this reason.
+
+```rust
+let (name, set_name) = create_signal(cx, "Controlled".to_string());
+
+view! { cx,
+    <input type="text"
+        on:input=move |ev| {
+            // event_target_value is a Leptos helper function
+            // it functions the same way as event.target.value
+            // in JavaScript, but smooths out some of the typecasting
+            // necessary to make this work in Rust
+            set_name(event_target_value(&ev));
+        }
+
+        // the `prop:` syntax lets you update a DOM property,
+        // rather than an attribute.
+        prop:value=name
+    />
+    <p>"Name is: " {name}</p>
+}
+```
+
+## Uncontrolled Inputs 
+
+In an "uncontrolled input," the browser controls the state of the input element. 
+Rather than continuously updating a signal to hold its value, we use a 
+[`NodeRef`](https://docs.rs/leptos/latest/leptos/struct.NodeRef.html) to access 
+the input once when we want to get its value.
+
+In this example, we only notify the framework when the `<form>` fires a `submit` 
+event.
+
+```rust
+let (name, set_name) = create_signal(cx, "Uncontrolled".to_string());
+
+let input_element: NodeRef<HtmlElement<Input>> = NodeRef::new(cx);
+```
+`NodeRef` is a kind of reactive smart pointer: we can use it to access the 
+underlying DOM node. Its value will be set when the element is rendered.
+
+```rust
+let on_submit = move |ev: SubmitEvent| {
+    // stop the page from reloading!
+    ev.prevent_default();
+
+    // here, we'll extract the value from the input
+    let value = input_element()
+        // event handlers can only fire after the view
+        // is mounted to the DOM, so the `NodeRef` will be `Some`
+        .expect("<input> to exist")
+        // `NodeRef` implements `Deref` for the DOM element type
+        // this means we can call`HtmlInputElement::value()`
+        // to get the current value of the input
+        .value();
+    set_name(value);
+};
+```
+Our `on_submit` handler will access the input’s value and use it to call `set_name`.
+To access the DOM node stored in the `NodeRef`, we can simply call it as a function
+(or using `.get()`). This will return `Option<web_sys::HtmlInputElement>`, but we 
+know it will already have been filled when we rendered the view, so it’s safe to 
+unwrap here.
+
+We can then call `.value()` to get the value out of the input, because `NodeRef` 
+gives us access to a correctly-typed HTML element.
+
+```rust
+view! { cx,
+    <form on:submit=on_submit>
+        <input type="text"
+            value=name
+            node_ref=input_element
+        />
+        <input type="submit" value="Submit"/>
+    </form>
+    <p>"Name is: " {name}</p>
+}
+```
+The view should be pretty self-explanatory by now. Note two things:
+1. Unlike in the controlled input example, we use `value` (not `prop:value`).
+   This is because we’re just setting the initial value of the input, and letting 
+   the browser control its state. (We could use `prop:value` instead.)
+2. We use `node_ref` to fill the `NodeRef`. (Older examples sometimes use `_ref`.
+   They are the same thing, but `node_ref` has better rust-analyzer support.)
+
+<iframe src="https://codesandbox.io/p/sandbox/5-form-inputs-ih9m62?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A12%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A12%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/06_control_flow.md

@@ -0,0 +1,285 @@
+# Control Flow
+
+In most applications, you sometimes need to make a decision: Should I render this
+part of the view, or not? Should I render `<ButtonA/>` or `<WidgetB/>`? This is
+**control flow**.
+
+## A Few Tips
+
+When thinking about how to do this with Leptos, it’s important to remember a few
+things:
+
+1. Rust is an expression-oriented language: control-flow expressions like
+   `if x() { y } else { z }` and `match x() { ... }` return their values. This
+   makes them very useful for declarative user interfaces.
+2. For any `T` that implements `IntoView`—in other words, for any type that Leptos
+   knows how to render—`Option<T>` and `Result<T, impl Error>` _also_ implement
+   `IntoView`. And just as `Fn() -> T` renders a reactive `T`, `Fn() -> Option<T>`
+   and `Fn() -> Result<T, impl Error>` are reactive.
+3. Rust has lots of handy helpers like [Option::map](https://doc.rust-lang.org/std/option/enum.Option.html#method.map),
+   [Option::and_then](https://doc.rust-lang.org/std/option/enum.Option.html#method.and_then),
+   [Option::ok_or](https://doc.rust-lang.org/std/option/enum.Option.html#method.ok_or),
+   [Result::map](https://doc.rust-lang.org/std/result/enum.Result.html#method.map),
+   [Result::ok](https://doc.rust-lang.org/std/result/enum.Result.html#method.ok), and
+   [bool::then](https://doc.rust-lang.org/std/primitive.bool.html#method.then) that
+   allow you to convert, in a declarative way, between a few different standard types,
+   all of which can be rendered. Spending time in the `Option` and `Result` docs in particular
+   is one of the best ways to level up your Rust game.
+4. And always remember: to be reactive, values must be functions. You’ll see me constantly
+   wrap things in a `move ||` closure, below. This is to ensure that they actually re-run
+   when the signal they depend on changes, keeping the UI reactive.
+
+## So What?
+
+To connect the dots a little: this means that you can actually implement most of
+your control flow with native Rust code, without any control-flow components or
+special knowledge.
+
+For example, let’s start with a simple signal and derived signal:
+
+```rust
+let (value, set_value) = create_signal(cx, 0);
+let is_odd = move || value() & 1 == 1;
+```
+
+> If you don’t recognize what’s going on with `is_odd`, don’t worry about it
+> too much. It’s just a simple way to test whether an integer is odd by doing a
+> bitwise `AND` with `1`.
+
+We can use these signals and ordinary Rust to build most control flow.
+
+### `if` statements
+
+Let’s say I want to render some text if the number is odd, and some other text
+if it’s even. Well, how about this?
+
+```rust
+view! { cx,
+	<p>
+	{move || if is_odd() {
+		"Odd"
+	} else {
+		"Even"
+	}}
+	</p>
+}
+```
+
+An `if` expression returns its value, and a `&str` implements `IntoView`, so a
+`Fn() -> &str` implements `IntoView`, so this... just works!
+
+### `Option<T>`
+
+Let’s say we want to render some text if it’s odd, and nothing if it’s even.
+
+```rust
+let message = move || {
+	if is_odd() {
+		Some("Ding ding ding!")
+	} else {
+		None
+	}
+};
+
+view! { cx,
+	<p>{message}</p>
+}
+```
+
+This works fine. We can make it a little shorter if we’d like, using `bool::then()`.
+
+```rust
+let message = move || is_odd().then(|| "Ding ding ding!");
+view! { cx,
+	<p>{message}</p>
+}
+```
+
+You could even inline this if you’d like, although personally I sometimes like the
+better `cargo fmt` and `rust-analyzer` support I get by pulling things out of the `view`.
+
+### `match` statements
+
+We’re still just writing ordinary Rust code, right? So you have all the power of Rust’s
+pattern matching at your disposal.
+
+```rust
+let message = move || {
+	match value() {
+		0 => "Zero",
+		1 => "One",
+		n if is_odd() => "Odd",
+		_ => "Even"
+	}
+};
+view! { cx,
+	<p>{message}</p>
+}
+```
+
+And why not? YOLO, right?
+
+## Preventing Over-Rendering
+
+Not so YOLO.
+
+Everything we’ve just done is basically fine. But there’s one thing you should remember
+and try to be careful with. Each one of the control-flow functions we’ve created so far
+is basically a derived signal: it will rerun every time the value changes. In the examples
+above, where the value switches from even to odd on every change, this is fine.
+
+But consider the following example:
+
+```rust
+let (value, set_value) = create_signal(cx, 0);
+
+let message = move || if value() > 5 {
+	"Big"
+} else {
+	"Small"
+};
+
+view! { cx,
+	<p>{message}</p>
+}
+```
+
+This _works_, for sure. But if you added a log, you might be surprised
+
+```rust
+let message = move || if value() > 5 {
+	log!("{}: rendering Big", value());
+	"Big"
+} else {
+	log!("{}: rendering Small", value());
+	"Small"
+};
+```
+
+As a user clicks a button, you’d see something like this:
+
+```
+1: rendering Small
+2: rendering Small
+3: rendering Small
+4: rendering Small
+5: rendering Small
+6: rendering Big
+7: rendering Big
+8: rendering Big
+... ad infinitum
+```
+
+Every time `value` changes, it reruns the `if` statement. This makes sense, with
+how reactivity works. But it has a downside. For a simple text node, rerunning
+the `if` statement and rerendering isn’t a big deal. But imagine it were
+like this:
+
+```rust
+let message = move || if value() > 5 {
+	<Big/>
+} else {
+	<Small/>
+};
+```
+
+This rerenders `<Small/>` five times, then `<Big/>` infinitely. If they’re
+loading resources, creating signals, or even just creating DOM nodes, this is
+unnecessary work.
+
+### `<Show/>`
+
+The [`<Show/>`](https://docs.rs/leptos/latest/leptos/fn.Show.html) component is
+the answer. You pass it a `when` condition function, a `fallback` to be shown if
+the `when` function returns `false`, and children to be rendered if `when` is `true`.
+
+```rust
+let (value, set_value) = create_signal(cx, 0);
+
+view! { cx,
+  <Show
+    when=move || value() > 5
+    fallback=|cx| view! { cx, <Small/> }
+  >
+    <Big/>
+  </Show>
+}
+```
+
+`<Show/>` memoizes the `when` condition, so it only renders its `<Small/>` once,
+continuing to show the same component until `value` is greater than five;
+then it renders `<Big/>` once, continuing to show it indefinitely.
+
+This is a helpful tool to avoid rerendering when using dynamic `if` expressions.
+As always, there's some overhead: for a very simple node (like updating a single
+text node, or updating a class or attribute), a `move || if ...` will be more
+efficient. But if it’s at all expensive to render either branch, reach for
+`<Show/>`.
+
+## Note: Type Conversions
+
+There‘s one final thing it’s important to say in this section.
+
+The `view` macro doesn’t return the most-generic wrapping type
+[`View`](https://docs.rs/leptos/latest/leptos/enum.View.html).
+Instead, it returns things with types like `Fragment` or `HtmlElement<Input>`. This
+can be a little annoying if you’re returning different HTML elements from
+different branches of a conditional:
+
+```rust,compile_error
+view! { cx,
+	<main>
+		{move || match is_odd() {
+			true if value() == 1 => {
+				// returns HtmlElement<Pre>
+				view! { cx, <pre>"One"</pre> }
+			},
+			false if value() == 2 => {
+				// returns HtmlElement<P>
+				view! { cx, <p>"Two"</p> }
+			}
+			// returns HtmlElement<Textarea>
+			_ => view! { cx, <textarea>{value()}</textarea> }
+		}}
+	</main>
+}
+```
+
+This strong typing is actually very powerful, because
+[`HtmlElement`](https://docs.rs/leptos/0.1.3/leptos/struct.HtmlElement.html) is,
+among other things, a smart pointer: each `HtmlElement<T>` type implements
+`Deref` for the appropriate underlying `web_sys` type. In other words, in the browser
+your `view` returns real DOM elements, and you can access native DOM methods on
+them.
+
+But it can be a little annoying in conditional logic like this, because you can’t
+return different types from different branches of a condition in Rust. There are two ways
+to get yourself out of this situation:
+
+1. If you have multiple `HtmlElement` types, convert them to `HtmlElement<AnyElement>`
+   with [`.into_any()`](https://docs.rs/leptos/latest/leptos/struct.HtmlElement.html#method.into_any)
+2. If you have a variety of view types that are not all `HtmlElement`, convert them to
+   `View`s with [`.into_view(cx)`](https://docs.rs/leptos/latest/leptos/trait.IntoView.html#tymethod.into_view).
+
+Here’s the same example, with the conversion added:
+
+```rust,compile_error
+view! { cx,
+	<main>
+		{move || match is_odd() {
+			true if value() == 1 => {
+				// returns HtmlElement<Pre>
+				view! { cx, <pre>"One"</pre> }.into_any()
+			},
+			false if value() == 2 => {
+				// returns HtmlElement<P>
+				view! { cx, <p>"Two"</p> }.into_any()
+			}
+			// returns HtmlElement<Textarea>
+			_ => view! { cx, <textarea>{value()}</textarea> }.into_any()
+		}}
+	</main>
+}
+```
+
+<iframe src="https://codesandbox.io/p/sandbox/6-control-flow-in-view-zttwfx?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A2%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A2%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/07_errors.md

@@ -0,0 +1,115 @@
+# Error Handling
+
+[In the last chapter](./06_control_flow.md), we saw that you can render `Option<T>`:
+in the `None` case, it will render nothing, and in the `T` case, it will render `T`
+(that is, if `T` implements `IntoView`). You can actually do something very similar
+with a `Result<T, E>`. In the `Err(_)` case, it will render nothing. In the `Ok(T)`
+case, it will render the `T`.
+
+Let’s start with a simple component to capture a number input.
+
+```rust
+#[component]
+fn NumericInput(cx: Scope) -> impl IntoView {
+    let (value, set_value) = create_signal(cx, Ok(0));
+
+    // when input changes, try to parse a number from the input
+    let on_input = move |ev| set_value(event_target_value(&ev).parse::<i32>());
+
+    view! { cx,
+        <label>
+            "Type a number (or not!)"
+            <input type="number" on:input=on_input/>
+            <p>
+                "You entered "
+                <strong>{value}</strong>
+            </p>
+        </label>
+    }
+}
+```
+
+Every time you change the input, `on_input` will attempt to parse its value into a 32-bit
+integer (`i32`), and store it in our `value` signal, which is a `Result<i32, _>`. If you
+type the number `42`, the UI will display
+
+```
+You entered 42
+```
+
+But if you type the string`foo`, it will display
+
+```
+You entered
+```
+
+This is not great. It saves us using `.unwrap_or_default()` or something, but it would be
+much nicer if we could catch the error and do something with it.
+
+You can do that, with the [`<ErrorBoundary/>`](https://docs.rs/leptos/latest/leptos/fn.ErrorBoundary.html)
+component.
+
+## `<ErrorBoundary/>`
+
+An `<ErrorBoundary/>` is a little like the `<Show/>` component we saw in the last chapter.
+If everything’s okay—which is to say, if everything is `Ok(_)`—it renders its children.
+But if there’s an `Err(_)` rendered among those children, it will trigger the
+`<ErrorBoundary/>`’s `fallback`.
+
+Let’s add an `<ErrorBoundary/>` to this example.
+
+```rust
+#[component]
+fn NumericInput(cx: Scope) -> impl IntoView {
+    let (value, set_value) = create_signal(cx, Ok(0));
+
+let on_input = move |ev| set_value(event_target_value(&ev).parse::<i32>());
+
+    view! { cx,
+        <h1>"Error Handling"</h1>
+        <label>
+            "Type a number (or something that's not a number!)"
+            <input type="number" on:input=on_input/>
+            <ErrorBoundary
+                // the fallback receives a signal containing current errors
+                fallback=|cx, errors| view! { cx,
+                    <div class="error">
+                        <p>"Not a number! Errors: "</p>
+                        // we can render a list of errors as strings, if we'd like
+                        <ul>
+                            {move || errors.unwrap()
+                                .get()
+                                .0
+                                .into_iter()
+                                .map(|(_, e)| view! { cx, <li>{e.to_string()}</li>})
+                                .collect::<Vec<_>>()
+                            }
+                        </ul>
+                    </div>
+                }
+            >
+                <p>"You entered " <strong>{value}</strong></p>
+            </ErrorBoundary>
+        </label>
+    }
+}
+```
+
+Now, if you type `42`, `value` is `Ok(42)` and you’ll see
+
+```
+You entered 42
+```
+
+If you type `foo`, value is `Err(_)` and the `fallback` will render. We’ve chosen to render
+the list of errors as a `String`, so you’ll see something like
+
+```
+Not a number! Errors:
+- cannot parse integer from empty string
+```
+
+If you fix the error, the error message will disappear and the content you’re wrapping in
+an `<ErrorBoundary/>` will appear again.
+
+<iframe src="https://codesandbox.io/p/sandbox/7-error-handling-and-error-boundaries-sroncx?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A2%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A2%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/08_parent_child.md

@@ -0,0 +1,286 @@
+# Parent-Child Communication
+
+You can think of your application as a nested tree of components. Each component
+handles its own local state and manages a section of the user interface, so
+components tend to be relatively self-contained.
+
+Sometimes, though, you’ll want to communicate between a parent component and its
+child. For example, imagine you’ve defined a `<FancyButton/>` component that adds
+some styling, logging, or something else to a `<button/>`. You want to use a
+`<FancyButton/>` in your `<App/>` component. But how can you communicate between
+the two?
+
+It’s easy to communicate state from a parent component to a child component. We
+covered some of this in the material on [components and props](./03_components.md).
+Basically if you want the parent to communicate to the child, you can pass a
+[`ReadSignal`](https://docs.rs/leptos/latest/leptos/struct.ReadSignal.html), a
+[`Signal`](https://docs.rs/leptos/latest/leptos/struct.Signal.html), or even a
+[`MaybeSignal`](https://docs.rs/leptos/latest/leptos/struct.MaybeSignal.html) as a prop.
+
+But what about the other direction? How can a child send notifications about events
+or state changes back up to the parent?
+
+There are four basic patterns of parent-child communication in Leptos.
+
+## 1. Pass a [`WriteSignal`](https://docs.rs/leptos/latest/leptos/struct.WriteSignal.html)
+
+One approach is simply to pass a `WriteSignal` from the parent down to the child, and update
+it in the child. This lets you manipulate the state of the parent from the child.
+
+```rust
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+	let (toggled, set_toggled) = create_signal(cx, false);
+	view! { cx,
+		<p>"Toggled? " {toggled}</p>
+		<ButtonA setter=set_toggled/>
+	}
+}
+
+#[component]
+pub fn ButtonA(cx: Scope, setter: WriteSignal<bool>) -> impl IntoView {
+    view! { cx,
+        <button
+            on:click=move |_| setter.update(|value| *value = !*value)
+        >
+            "Toggle"
+        </button>
+    }
+}
+```
+
+This pattern is simple, but you should be careful with it: passing around a `WriteSignal`
+can make it hard to reason about your code. In this example, it’s pretty clear when you
+read `<App/>` that you are handing off the ability to mutate `toggled`, but it’s not at
+all clear when or how it will change. In this small, local example it’s easy to understand,
+but if you find yourself passing around `WriteSignal`s like this throughout your code,
+you should really consider whether this is making it too easy to write spaghetti code.
+
+## 2. Use a Callback
+
+Another approach would be to pass a callback to the child: say, `on_click`.
+
+```rust
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+	let (toggled, set_toggled) = create_signal(cx, false);
+	view! { cx,
+		<p>"Toggled? " {toggled}</p>
+		<ButtonB on_click=move |_| set_toggled.update(|value| *value = !*value)/>
+	}
+}
+
+
+#[component]
+pub fn ButtonB<F>(
+    cx: Scope,
+    on_click: F,
+) -> impl IntoView
+where
+    F: Fn(MouseEvent) + 'static,
+{
+    view! { cx,
+        <button on:click=on_click>
+            "Toggle"
+        </button>
+    }
+}
+```
+
+You’ll notice that whereas `<ButtonA/>` was given a `WriteSignal` and decided how to mutate it,
+`<ButtonB/>` simply fires an event: the mutation happens back in `<App/>`. This has the advantage
+of keeping local state local, preventing the problem of spaghetti mutation. But it also means
+the logic to mutate that signal needs to exist up in `<App/>`, not down in `<ButtonB/>`. These
+are real trade-offs, not a simple right-or-wrong choice.
+
+> Note the way we declare the generic type `F` here for the callback. If you’re
+> confused, look back at the [generic props](./03_components.html#generic-props) section
+> of the chapter on components.
+
+## 3. Use an Event Listener
+
+You can actually write Option 2 in a slightly different way. If the callback maps directly onto
+a native DOM event, you can add an `on:` listener directly to the place you use the component
+in your `view` macro in `<App/>`.
+
+```rust
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+	let (toggled, set_toggled) = create_signal(cx, false);
+	view! { cx,
+		<p>"Toggled? " {toggled}</p>
+		// note the on:click instead of on_click
+		// this is the same syntax as an HTML element event listener
+		<ButtonC on:click=move |_| set_toggled.update(|value| *value = !*value)/>
+	}
+}
+
+
+#[component]
+pub fn ButtonC<F>(cx: Scope) -> impl IntoView {
+    view! { cx,
+        <button>"Toggle"</button>
+    }
+}
+```
+
+This lets you write way less code in `<ButtonC/>` than you did for `<ButtonB/>`,
+and still gives a correctly-typed event to the listener. This works by adding an
+`on:` event listener to each element that `<ButtonC/>` returns: in this case, just
+the one `<button>`.
+
+Of course, this only works for actual DOM events that you’re passing directly through
+to the elements you’re rendering in the component. For more complex logic that
+doesn’t map directly onto an element (say you create `<ValidatedForm/>` and want an
+`on_valid_form_submit` callback) you should use Option 2.
+
+## 4. Providing a Context
+
+This version is actually a variant on Option 1. Say you have a deeply-nested component
+tree:
+
+```rust
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+	let (toggled, set_toggled) = create_signal(cx, false);
+	view! { cx,
+		<p>"Toggled? " {toggled}</p>
+		<Layout/>
+	}
+}
+
+#[component]
+pub fn Layout(cx: Scope) -> impl IntoView {
+	view! { cx,
+		<header>
+			<h1>"My Page"</h1>
+		<main>
+			<Content/>
+		</main>
+	}
+}
+
+#[component]
+pub fn Content(cx: Scope) -> impl IntoView {
+	view! { cx,
+		<div class="content">
+			<ButtonD/>
+		</div>
+	}
+}
+
+#[component]
+pub fn ButtonD<F>(cx: Scope) -> impl IntoView {
+    todo!()
+}
+```
+
+Now `<ButtonD/>` is no longer a direct child of `<App/>`, so you can’t simply
+pass your `WriteSignal` to its props. You could do what’s sometimes called
+“prop drilling,” adding a prop to each layer between the two:
+
+```rust
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+	let (toggled, set_toggled) = create_signal(cx, false);
+	view! { cx,
+		<p>"Toggled? " {toggled}</p>
+		<Layout set_toggled/>
+	}
+}
+
+#[component]
+pub fn Layout(cx: Scope, set_toggled: WriteSignal<bool>) -> impl IntoView {
+	view! { cx,
+		<header>
+			<h1>"My Page"</h1>
+		<main>
+			<Content set_toggled/>
+		</main>
+	}
+}
+
+#[component]
+pub fn Content(cx: Scope, set_toggled: WriteSignal<bool>) -> impl IntoView {
+	view! { cx,
+		<div class="content">
+			<ButtonD set_toggled/>
+		</div>
+	}
+}
+
+#[component]
+pub fn ButtonD<F>(cx: Scope, set_toggled: WriteSignal<bool>) -> impl IntoView {
+    todo!()
+}
+```
+
+This is a mess. `<Layout/>` and `<Content/>` don’t need `set_toggled`; they just
+pass it through to `<ButtonD/>`. But I need to declare the prop in triplicate.
+This is not only annoying but hard to maintain: imagine we add a “half-toggled”
+option and the type of `set_toggled` needs to change to an `enum`. We have to change
+it in three places!
+
+Isn’t there some way to skip levels?
+
+There is!
+
+### The Context API
+
+You can provide data that skips levels by using [`provide_context`](https://docs.rs/leptos/latest/leptos/fn.provide_context.html)
+and [`use_context`](https://docs.rs/leptos/latest/leptos/fn.use_context.html). Contexts are identified
+by the type of the data you provide (in this example, `WriteSignal<bool>`), and they exist in a top-down
+tree that follows the contours of your UI tree. In this example, we can use context to skip the
+unnecessary prop drilling.
+
+```rust
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+	let (toggled, set_toggled) = create_signal(cx, false);
+
+	// share `set_toggled` with all children of this component
+	provide_context(cx, set_toggled);
+
+	view! { cx,
+		<p>"Toggled? " {toggled}</p>
+		<Layout/>
+	}
+}
+
+// <Layout/> and <Content/> omitted
+
+#[component]
+pub fn ButtonD(cx: Scope) -> impl IntoView {
+	// use_context searches up the context tree, hoping to
+	// find a `WriteSignal<bool>`
+	// in this case, I .expect() because I know I provided it
+	let setter = use_context::<WriteSignal<bool>>(cx)
+		.expect("to have found the setter provided");
+
+    view! { cx,
+        <button
+            on:click=move |_| setter.update(|value| *value = !*value)
+        >
+            "Toggle"
+        </button>
+    }
+}
+```
+
+The same caveats apply to this as to `<ButtonA/>`: passing a `WriteSignal`
+around should be done with caution, as it allows you to mutate state from
+arbitrary parts of your code. But when done carefully, this can be one of
+the most effective techniques for global state management in Leptos: simply
+provide the state at the highest level you’ll need it, and use it wherever
+you need it lower down.
+
+Note that there are no performance downsides to this approach. Because you
+are passing a fine-grained reactive signal, _nothing happens_ in the intervening
+components (`<Layout/>` and `<Content/>`) when you update it. You are communicating
+directly between `<ButtonD/>` and `<App/>`. In fact—and this is the power of
+fine-grained reactivity—you are communicating directly between a button click
+in `<ButtonD/>` and a single text node in `<App/>`. It’s as if the components
+themselves don’t exist at all. And, well... at runtime, they don’t. It’s just
+signals and effects, all the way down.
+
+<iframe src="https://codesandbox.io/p/sandbox/8-parent-child-communication-84we8m?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A1%2C%22endLineNumber%22%3A3%2C%22startColumn%22%3A1%2C%22startLineNumber%22%3A3%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/09_component_children.md

@@ -0,0 +1,126 @@
+# Component Children
+
+It’s pretty common to want to pass children into a component, just as you can pass
+children into an HTML element. For example, imagine I have a `<FancyForm/>` component
+that enhances an HTML `<form>`. I need some way to pass all its inputs.
+
+```rust
+view! { cx,
+	<Form>
+		<fieldset>
+			<label>
+				"Some Input"
+				<input type="text" name="something"/>
+			</label>
+		</fieldset>
+		<button>"Submit"</button>
+	</Form>
+}
+```
+
+How can you do this in Leptos? There are basically two ways to pass components to
+other components:
+
+1. **render props**: properties that are functions that return a view
+2. the **`children`** prop: a special component property that includes anything
+   you pass as a child to the component.
+
+In fact, you’ve already seen these both in action in the [`<Show/>`](/view/06_control_flow.html#show) component:
+
+```rust
+view! { cx,
+  <Show
+	// `when` is a normal prop
+    when=move || value() > 5
+	// `fallback` is a "render prop": a function that returns a view
+    fallback=|cx| view! { cx, <Small/> }
+  >
+	// `<Big/>` (and anything else here)
+	// will be given to the `children` prop
+    <Big/>
+  </Show>
+}
+```
+
+Let’s define a component that takes some children and a render prop.
+
+```rust
+#[component]
+pub fn TakesChildren<F, IV>(
+    cx: Scope,
+    /// Takes a function (type F) that returns anything that can be
+    /// converted into a View (type IV)
+    render_prop: F,
+    /// `children` takes the `Children` type
+    children: Children,
+) -> impl IntoView
+where
+    F: Fn() -> IV,
+    IV: IntoView,
+{
+    view! { cx,
+        <h2>"Render Prop"</h2>
+        {render_prop()}
+
+		<h2>"Children"</h2>
+        {children(cx)}
+    }
+}
+```
+
+`render_prop` and `children` are both functions, so we can call them to generate
+the appropriate views. `children`, in particular, is an alias for
+`Box<dyn FnOnce(Scope) -> Fragment>`. (Aren't you glad we named it `Children` instead?)
+
+> If you need a `Fn` or `FnMut` here because you need to call `children` more than once,
+> we also provide `ChildrenFn` and `ChildrenMut` aliases.
+
+We can use the component like this:
+
+```rust
+view! { cx,
+	<TakesChildren render_prop=|| view! { cx, <p>"Hi, there!"</p> }>
+		// these get passed to `children`
+		"Some text"
+		<span>"A span"</span>
+	</TakesChildren>
+}
+```
+
+## Manipulating Children
+
+The [`Fragment`](https://docs.rs/leptos/latest/leptos/struct.Fragment.html) type is
+basically a way of wrapping a `Vec<View>`. You can insert it anywhere into your view.
+
+But you can also access those inner views directly to manipulate them. For example, here’s
+a component that takes its children and turns them into an unordered list.
+
+```rust
+#[component]
+pub fn WrapsChildren(cx: Scope, children: Children) -> impl IntoView {
+    // Fragment has `nodes` field that contains a Vec<View>
+    let children = children(cx)
+        .nodes
+        .into_iter()
+        .map(|child| view! { cx, <li>{child}</li> })
+        .collect::<Vec<_>>();
+
+    view! { cx,
+        <ul>{children}</ul>
+    }
+}
+```
+
+Calling it like this will create a list:
+
+```rust
+view! { cx,
+	<WrappedChildren>
+		"A"
+		"B"
+		"C"
+	</WrappedChildren>
+}
+```
+
+<iframe src="https://codesandbox.io/p/sandbox/9-component-children-2wrdfd?file=%2Fsrc%2Fmain.rs&selection=%5B%7B%22endColumn%22%3A12%2C%22endLineNumber%22%3A19%2C%22startColumn%22%3A12%2C%22startLineNumber%22%3A19%7D%5D" width="100%" height="1000px"></iframe>

docs/book/src/view/README.md

@@ -0,0 +1,5 @@
+# Building User Interfaces
+
+This first section will introduce you to the basic tools you need to build a reactive
+user interface using Leptos. By the end of this section, you should be able to 
+build a simple, synchronous application that is rendered in the browser.

examples/counter/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/counter/tests/mod.rs

@@ -1,16 +1,86 @@
 use wasm_bindgen_test::*;
 
 wasm_bindgen_test_configure!(run_in_browser);
+use counter::*;
 use leptos::*;
 use web_sys::HtmlElement;
-use counter::*;
+
+#[wasm_bindgen_test]
+fn clear() {
+    let document = leptos::document();
+    let test_wrapper = document.create_element("section").unwrap();
+    document.body().unwrap().append_child(&test_wrapper);
+
+    // start by rendering our counter and mounting it to the DOM
+    // note that we start at the initial value of 10
+    mount_to(
+        test_wrapper.clone().unchecked_into(),
+        |cx| view! { cx, <SimpleCounter initial_value=10 step=1/> },
+    );
+
+    // now we extract the buttons by iterating over the DOM
+    // this would be easier if they had IDs
+    let div = test_wrapper.query_selector("div").unwrap().unwrap();
+    let clear = test_wrapper
+        .query_selector("button")
+        .unwrap()
+        .unwrap()
+        .unchecked_into::<web_sys::HtmlElement>();
+
+    // now let's click the `clear` button
+    clear.click();
+
+    // now let's test the <div> against the expected value
+    // we can do this by testing its `outerHTML`
+    assert_eq!(
+        div.outer_html(),
+        // here we spawn a mini reactive system, just to render the
+        // test case
+        run_scope(create_runtime(), |cx| {
+            // it's as if we're creating it with a value of 0, right?
+            let (value, set_value) = create_signal(cx, 0);
+
+            // we can remove the event listeners because they're not rendered to HTML
+            view! { cx,
+                <div>
+                    <button>"Clear"</button>
+                    <button>"-1"</button>
+                    <span>"Value: " {value} "!"</span>
+                    <button>"+1"</button>
+                </div>
+            }
+            // the view returned an HtmlElement<Div>, which is a smart pointer for
+            // a DOM element. So we can still just call .outer_html()
+            .outer_html()
+        })
+    );
+
+    // There's actually an easier way to do this...
+    // We can just test against a <SimpleCounter/> with the initial value 0
+    assert_eq!(test_wrapper.inner_html(), {
+        let comparison_wrapper = document.create_element("section").unwrap();
+        leptos::mount_to(
+            comparison_wrapper.clone().unchecked_into(),
+            |cx| view! { cx, <SimpleCounter initial_value=0 step=1/>},
+        );
+        comparison_wrapper.inner_html()
+    });
+}
 
 #[wasm_bindgen_test]
 fn inc() {
-    mount_to_body(|cx| view! { cx, <SimpleCounter initial_value=0 step=1/> });
-
     let document = leptos::document();
-    let div = document.query_selector("div").unwrap().unwrap();
+    let test_wrapper = document.create_element("section").unwrap();
+    document.body().unwrap().append_child(&test_wrapper);
+
+    mount_to(
+        test_wrapper.clone().unchecked_into(),
+        |cx| view! { cx, <SimpleCounter initial_value=0 step=1/> },
+    );
+
+    // You can do testing with vanilla DOM operations
+    let document = leptos::document();
+    let div = test_wrapper.query_selector("div").unwrap().unwrap();
     let clear = div
         .first_child()
         .unwrap()
@@ -47,4 +117,40 @@ fn inc() {
     clear.click();
 
     assert_eq!(text.text_content(), Some("Value: 0!".to_string()));
+
+    // Or you can test against a sample view!
+    assert_eq!(
+        div.outer_html(),
+        run_scope(create_runtime(), |cx| {
+            let (value, _) = create_signal(cx, 0);
+            view! { cx,
+                <div>
+                    <button>"Clear"</button>
+                    <button>"-1"</button>
+                    <span>"Value: " {value} "!"</span>
+                    <button>"+1"</button>
+                </div>
+            }
+        }
+        .outer_html())
+    );
+
+    inc.click();
+
+    assert_eq!(
+        div.outer_html(),
+        run_scope(create_runtime(), |cx| {
+            // because we've clicked, it's as if the signal is starting at 1
+            let (value, _) = create_signal(cx, 1);
+            view! { cx,
+                <div>
+                    <button>"Clear"</button>
+                    <button>"-1"</button>
+                    <span>"Value: " {value} "!"</span>
+                    <button>"+1"</button>
+                </div>
+            }
+        }
+        .outer_html())
+    );
 }

examples/counter_isomorphic/Cargo.toml

@@ -8,7 +8,7 @@ crate-type = ["cdylib", "rlib"]
 
 [dependencies]
 actix-files = { version = "0.6", optional = true }
-actix-web = { version = "4", optional = true, features = ["openssl", "macros"] }
+actix-web = { version = "4", optional = true, features = ["macros"] }
 broadcaster = "1"
 console_log = "0.2"
 console_error_panic_hook = "0.1"
@@ -25,6 +25,7 @@ leptos_router = { path = "../../router", default-features = false }
 log = "0.4"
 simple_logger = "4.0.0"
 gloo-net = { git = "https://github.com/rustwasm/gloo" }
+wasm-bindgen = "0.2"
 
 [features]
 default = []

examples/counter_isomorphic/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/counter_isomorphic/src/counters.rs

@@ -97,10 +97,10 @@ pub fn Counter(cx: Scope) -> impl IntoView {
         |_| get_server_count(),
     );
 
-    let value = move || counter.read().map(|count| count.unwrap_or(0)).unwrap_or(0);
+    let value = move || counter.read(cx).map(|count| count.unwrap_or(0)).unwrap_or(0);
     let error_msg = move || {
         counter
-            .read()
+            .read(cx)
             .map(|res| match res {
                 Ok(_) => None,
                 Err(e) => Some(e),
@@ -143,7 +143,7 @@ pub fn FormCounter(cx: Scope) -> impl IntoView {
     let value = move || {
         log::debug!("FormCounter looking for value");
         counter
-            .read()
+            .read(cx)
             .map(|n| n.ok())
             .flatten()
             .map(|n| n)
@@ -194,16 +194,16 @@ pub fn MultiuserCounter(cx: Scope) -> impl IntoView {
         use futures::StreamExt;
 
         let mut source = gloo_net::eventsource::futures::EventSource::new("/api/events")
-            .expect_throw("couldn't connect to SSE stream");
+            .expect("couldn't connect to SSE stream");
         let s = create_signal_from_stream(
             cx,
             source.subscribe("message").unwrap().map(|value| {
                 value
-                    .expect_throw("no message event")
+                    .expect("no message event")
                     .1
                     .data()
                     .as_string()
-                    .expect_throw("expected string value")
+                    .expect("expected string value")
             }),
         );
 

examples/counter_isomorphic/src/main.rs

@@ -37,7 +37,7 @@ cfg_if! {
             // when not using cargo-leptos None must be replaced with Some("Cargo.toml")
             let conf = get_configuration(None).await.unwrap();
 
-            let addr = conf.leptos_options.site_address.clone();
+            let addr = conf.leptos_options.site_addr.clone();
             let routes = generate_route_list(|cx| view! { cx, <Counters/> });
 
             HttpServer::new(move || {

examples/counter_without_macros/Makefile.toml

@@ -0,0 +1,9 @@
+[tasks.build]
+command = "cargo"
+args = ["+nightly", "build-all-features"]
+install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/counter_without_macros/src/lib.rs

@@ -1,4 +1,4 @@
-use leptos::{ev, *};
+use leptos::{ev, html::*, *};
 
 pub struct Props {
     /// The starting value for the counter
@@ -25,7 +25,9 @@ pub fn view(cx: Scope, props: Props) -> impl IntoView {
         .child((
             cx,
             button(cx)
-                .on(ev::click, move |_| set_value.update(|value| *value -= step))
+                .on(ev::click, move |_| {
+                    set_value.update(|value| *value -= step)
+                })
                 .child((cx, "-1")),
         ))
         .child((
@@ -38,7 +40,9 @@ pub fn view(cx: Scope, props: Props) -> impl IntoView {
         .child((
             cx,
             button(cx)
-                .on(ev::click, move |_| set_value.update(|value| *value += step))
+                .on(ev::click, move |_| {
+                    set_value.update(|value| *value += step)
+                })
                 .child((cx, "+1")),
         ))
 }

examples/counters/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/counters/src/lib.rs

@@ -1,5 +1,4 @@
-use leptos::*;
-use leptos::{For, ForProps};
+use leptos::{For, ForProps, *};
 
 const MANY_COUNTERS: usize = 1000;
 
@@ -66,9 +65,8 @@ pub fn Counters(cx: Scope) -> impl IntoView {
                 <For
                     each=counters
                     key=|counter| counter.0
-                    view=move |(id, (value, set_value)): (usize, (ReadSignal<i32>, WriteSignal<i32>))| {
-                        view! {
-                            cx,
+                    view=move |cx, (id, (value, set_value)): (usize, (ReadSignal<i32>, WriteSignal<i32>))| {
+                        view! { cx,
                             <Counter id value set_value/>
                         }
                     }
@@ -85,9 +83,11 @@ fn Counter(
     value: ReadSignal<i32>,
     set_value: WriteSignal<i32>,
 ) -> impl IntoView {
-    let CounterUpdater { set_counters } = use_context(cx).unwrap_throw();
+    let CounterUpdater { set_counters } = use_context(cx).unwrap();
 
-    let input = move |ev| set_value(event_target_value(&ev).parse::<i32>().unwrap_or_default());
+    let input = move |ev| {
+        set_value(event_target_value(&ev).parse::<i32>().unwrap_or_default())
+    };
 
     // just an example of how a cleanup function works
     // this will run when the scope is disposed, i.e., when this row is deleted

examples/counters_stable/src/main.rs

@@ -72,7 +72,7 @@ pub fn Counters(cx: Scope) -> impl IntoView {
                 <For
                     each={move || counters.get()}
                     key={|counter| counter.0}
-                    view=move |(id, (value, set_value))| {
+                    view=move |cx, (id, (value, set_value))| {
                         view! {
                             cx,
                             <Counter id value set_value/>
@@ -91,9 +91,12 @@ fn Counter(
     value: ReadSignal<i32>,
     set_value: WriteSignal<i32>,
 ) -> impl IntoView {
-    let CounterUpdater { set_counters } = use_context(cx).unwrap_throw();
+    let CounterUpdater { set_counters } = use_context(cx).unwrap();
 
-    let input = move |ev| set_value.set(event_target_value(&ev).parse::<i32>().unwrap_or_default());
+    let input = move |ev| {
+        set_value
+            .set(event_target_value(&ev).parse::<i32>().unwrap_or_default())
+    };
 
     view! { cx,
         <li>

examples/error_boundary/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "error_boundary"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+leptos = { path = "../../leptos" }
+console_log = "0.2"
+log = "0.4"
+console_error_panic_hook = "0.1.7"

examples/error_boundary/Makefile.toml

@@ -0,0 +1,9 @@
+[tasks.build]
+command = "cargo"
+args = ["+nightly", "build-all-features"]
+install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/error_boundary/README.md

@@ -0,0 +1,7 @@
+# Leptos `<ErrorBoundary/>` Example
+
+This example shows how to handle basic errors using Leptos.
+
+To run it, just issue the `trunk serve --open` command in the example root. This will build the app, run it, and open a new browser to serve it.
+
+> If you don't have `trunk` installed, [click here for install instructions.](https://trunkrs.dev/)

examples/error_boundary/index.html

@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<link data-trunk rel="rust" data-wasm-opt="z"/>
+		<link data-trunk rel="icon" type="image/ico" href="/public/favicon.ico"/>
+	</head>
+	<body></body>
+</html>

examples/error_boundary/src/lib.rs

@@ -0,0 +1,48 @@
+use leptos::*;
+
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+    let (value, set_value) = create_signal(cx, Ok(0));
+
+    // when input changes, try to parse a number from the input
+    let on_input = move |ev| set_value(event_target_value(&ev).parse::<i32>());
+
+    view! { cx,
+        <h1>"Error Handling"</h1>
+        <label>
+            "Type a number (or something that's not a number!)"
+            <input type="number" on:input=on_input/>
+            // If an `Err(_) had been rendered inside the <ErrorBoundary/>,
+            // the fallback will be displayed. Otherwise, the children of the
+            // <ErrorBoundary/> will be displayed.
+            <ErrorBoundary
+                // the fallback receives a signal containing current errors
+                fallback=|cx, errors| view! { cx,
+                    <div class="error">
+                        <p>"Not a number! Errors: "</p>
+                        // we can render a list of errors
+                        // as strings, if we'd like
+                        <ul>
+                            {move || errors.get()
+                                .0
+                                .into_iter()
+                                .map(|(_, e)| view! { cx, <li>{e.to_string()}</li>})
+                                .collect::<Vec<_>>()
+                            }
+                        </ul>
+                    </div>
+                }
+            >
+                <p>
+                    "You entered "
+                    // because `value` is `Result<i32, _>`,
+                    // it will render the `i32` if it is `Ok`,
+                    // and render nothing and trigger the error boundary
+                    // if it is `Err`. It's a signal, so this will dynamically
+                    // update when `value` changes
+                    <strong>{value}</strong>
+                </p>
+            </ErrorBoundary>
+        </label>
+    }
+}

examples/error_boundary/src/main.rs

@@ -0,0 +1,12 @@
+use error_boundary::*;
+use leptos::*;
+
+pub fn main() {
+    _ = console_log::init_with_level(log::Level::Debug);
+    console_error_panic_hook::set_once();
+    mount_to_body(|cx| {
+        view! { cx,
+            <App/>
+        }
+    })
+}

examples/errors_axum/Cargo.toml

@@ -0,0 +1,98 @@
+[package]
+name = "errors_axum"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+anyhow = "1.0.66"
+console_log = "0.2.0"
+console_error_panic_hook = "0.1.7"
+futures = "0.3.25"
+cfg-if = "1.0.0"
+leptos = { path = "../../../leptos/leptos", default-features = false, features = [
+	"serde",
+] }
+leptos_axum = { path = "../../../leptos/integrations/axum", default-features = false, optional = true }
+leptos_meta = { path = "../../../leptos/meta", default-features = false }
+leptos_router = { path = "../../../leptos/router", default-features = false }
+leptos_reactive = { path = "../../../leptos/leptos_reactive", default-features = false }
+log = "0.4.17"
+simple_logger = "4.0.0"
+serde = { version = "1.0.148", features = ["derive"] }
+serde_json = "1.0.89"
+gloo-net = { version = "0.2.5", features = ["http"] }
+reqwest = { version = "0.11.13", features = ["json"] }
+axum = { version = "0.6.1", optional = true }
+tower = { version = "0.4.13", optional = true }
+tower-http = { version = "0.3.4", features = ["fs"], optional = true }
+tokio = { version = "1.22.0", features = ["full"], optional = true }
+http = { version = "0.2.8" }
+thiserror = "1.0.38"
+tracing = "0.1.37"
+wasm-bindgen = "0.2"
+
+[features]
+default = ["csr"]
+csr = ["leptos/csr", "leptos_meta/csr", "leptos_router/csr"]
+hydrate = ["leptos/hydrate", "leptos_meta/hydrate", "leptos_router/hydrate"]
+ssr = [
+	"dep:axum",
+	"dep:tower",
+	"dep:tower-http",
+	"dep:tokio",
+	"leptos/ssr",
+	"leptos_meta/ssr",
+	"leptos_router/ssr",
+	"dep:leptos_axum",
+]
+
+[package.metadata.cargo-all-features]
+denylist = ["axum", "tower", "tower-http", "tokio", "leptos_axum"]
+skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]
+
+[package.metadata.leptos]
+# The name used by wasm-bindgen/cargo-leptos for the JS/WASM bundle. Defaults to the crate name   
+output-name = "errors_axum"
+# The site root folder is where cargo-leptos generate all output. WARNING: all content of this folder will be erased on a rebuild. Use it in your server setup.
+site-root = "target/site"
+# The site-root relative folder where all compiled output (JS, WASM and CSS) is written
+# Defaults to pkg	
+site-pkg-dir = "pkg"
+# [Optional] The source CSS file. If it ends with .sass or .scss then it will be compiled by dart-sass into CSS. The CSS is optimized by Lightning CSS before being written to <site-root>/<site-pkg>/app.css
+style-file = "./style.css"
+# [Optional] Files in the asset-dir will be copied to the site-root directory
+assets-dir = "public"
+# The IP and port (ex: 127.0.0.1:3000) where the server serves the content. Use it in your server setup.
+site-addr = "127.0.0.1:3000"
+# The port to use for automatic reload monitoring
+reload-port = 3001
+# [Optional] Command to use when running end2end tests. It will run in the end2end dir.
+end2end-cmd = "npx playwright test"
+#  The browserlist query used for optimizing the CSS.
+browserquery = "defaults"
+# Set by cargo-leptos watch when building with tha tool. Controls whether autoreload JS will be included in the head
+watch = false
+# The environment Leptos will run in, usually either "DEV" or "PROD"
+env = "DEV"
+# The features to use when compiling the bin target
+#
+# Optional. Can be over-ridden with the command line parameter --bin-features
+bin-features = ["ssr"]
+
+# If the --no-default-features flag should be used when compiling the bin target
+#
+# Optional. Defaults to false.
+bin-default-features = false
+
+# The features to use when compiling the lib target
+#
+# Optional. Can be over-ridden with the command line parameter --lib-features
+lib-features = ["hydrate"]
+
+# If the --no-default-features flag should be used when compiling the lib target
+#
+# Optional. Defaults to false.
+lib-default-features = false

examples/errors_axum/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 Greg Johnston
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

examples/errors_axum/Makefile.toml

@@ -0,0 +1,9 @@
+[tasks.build]
+command = "cargo"
+args = ["+nightly", "build-all-features"]
+install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/errors_axum/README.md

@@ -0,0 +1,41 @@
+# Leptos Errors Demonstration with Axum
+This example demonstrates how Leptos Errors can work with an Axum backend on a server.
+
+## Client Side Rendering
+This example cannot be built as a trunk standalone CSR-only app as it requires the server to send status codes.
+
+## Server Side Rendering with cargo-leptos
+cargo-leptos is now the easiest and most featureful way to build server side rendered apps with hydration. It provides automatic recompilation of client and server code, wasm optimisation, CSS minification, and more! Check out more about it [here](https://github.com/akesson/cargo-leptos)
+
+1. Install cargo-leptos
+```bash
+cargo install --locked cargo-leptos
+``` 
+2. Build the site in watch mode, recompiling on file changes
+```bash
+cargo leptos watch
+```
+
+Open browser on [http://localhost:3000/](http://localhost:3000/)
+
+3. When ready to deploy, run
+```bash
+cargo leptos build --release
+```
+
+## Server Side Rendering without cargo-leptos
+To run it as a server side app with hydration, you'll need to have wasm-pack installed.
+
+0. Edit the `[package.metadata.leptos]` section and set `site-root` to `"."`. You'll also want to change the path of the `<StyleSheet / >` component in the root component to point towards the CSS file in the root. This tells leptos that the WASM/JS files generated by wasm-pack are available at `./pkg` and that the CSS files are no longer processed by cargo-leptos. Building to alternative folders is not supported at this time. You'll also want to edit the call to `get_configuration()` to pass in `Some(Cargo.toml)`, so that Leptos will read the settings instead of cargo-leptos. If you do so, your file/folder names cannot include dashes.
+1. Install wasm-pack
+```bash
+cargo install wasm-pack
+```
+2. Build the Webassembly used to hydrate the HTML from the server
+```bash
+wasm-pack build --target=web --debug --no-default-features --features=hydrate
+```
+3. Run the server to serve the Webassembly, JS, and HTML 
+```bash
+cargo run --no-default-features --features=ssr
+```

examples/errors_axum/src/error_template.rs

@@ -0,0 +1,59 @@
+use crate::errors::AppError;
+use cfg_if::cfg_if;
+use leptos::{Errors, *};
+#[cfg(feature = "ssr")]
+use leptos_axum::ResponseOptions;
+
+// A basic function to display errors served by the error boundaries.
+// Feel free to do more complicated things here than just displaying them.
+#[component]
+pub fn ErrorTemplate(
+    cx: Scope,
+    #[prop(optional)] outside_errors: Option<Errors>,
+    #[prop(optional)] errors: Option<RwSignal<Errors>>,
+) -> impl IntoView {
+    let errors = match outside_errors {
+        Some(e) => create_rw_signal(cx, e),
+        None => match errors {
+            Some(e) => e,
+            None => panic!("No Errors found and we expected errors!"),
+        },
+    };
+
+    // Get Errors from Signal
+    // Downcast lets us take a type that implements `std::error::Error`
+    let errors: Vec<AppError> = errors
+        .get()
+        .into_iter()
+        .filter_map(|(_, v)| v.downcast_ref::<AppError>().cloned())
+        .collect();
+    log!("Errors: {errors:#?}");
+
+    // Only the response code for the first error is actually sent from the server
+    // this may be customized by the specific application
+    cfg_if! { if #[cfg(feature="ssr")] {
+        let response = use_context::<ResponseOptions>(cx);
+        if let Some(response) = response {
+            response.set_status(errors[0].status_code());
+        }
+    }}
+
+    view! { cx,
+        <h1>{if errors.len() > 1 {"Errors"} else {"Error"}}</h1>
+        <For
+            // a function that returns the items we're iterating over; a signal is fine
+            each= move || {errors.clone().into_iter().enumerate()}
+            // a unique key for each item as a reference
+            key=|(index, _)| *index
+            // renders each item to a view
+            view=move |cx, error| {
+                let error_string = error.1.to_string();
+                let error_code= error.1.status_code();
+                view! { cx,
+                    <h2>{error_code.to_string()}</h2>
+                    <p>"Error: " {error_string}</p>
+                }
+            }
+        />
+    }
+}

examples/errors_axum/src/errors.rs

@@ -0,0 +1,19 @@
+use http::status::StatusCode;
+use thiserror::Error;
+
+#[derive(Debug, Clone, Error)]
+pub enum AppError {
+    #[error("Not Found")]
+    NotFound,
+    #[error("Internal Server Error")]
+    InternalServerError,
+}
+
+impl AppError {
+    pub fn status_code(&self) -> StatusCode {
+        match self {
+            AppError::NotFound => StatusCode::NOT_FOUND,
+            AppError::InternalServerError => StatusCode::INTERNAL_SERVER_ERROR,
+        }
+    }
+}

examples/errors_axum/src/fallback.rs

@@ -0,0 +1,45 @@
+use cfg_if::cfg_if;
+
+cfg_if! { if #[cfg(feature = "ssr")] {
+    use axum::{
+        body::{boxed, Body, BoxBody},
+        extract::Extension,
+        response::IntoResponse,
+        http::{Request, Response, StatusCode, Uri},
+    };
+    use axum::response::Response as AxumResponse;
+    use tower::ServiceExt;
+    use tower_http::services::ServeDir;
+    use std::sync::Arc;
+    use leptos::{LeptosOptions, Errors, view};
+    use crate::landing::{App, AppProps};
+
+    pub async fn file_and_error_handler(uri: Uri, Extension(options): Extension<Arc<LeptosOptions>>, req: Request<Body>) -> AxumResponse {
+        let options = &*options;
+        let root = options.site_root.clone();
+        let res = get_static_file(uri.clone(), &root).await.unwrap();
+
+        if res.status() == StatusCode::OK {
+           res.into_response()
+        } else{
+            let handler = leptos_axum::render_app_to_stream(
+                options.to_owned(),
+                move |cx| view!{ cx, <App/> }
+            );
+            handler(req).await.into_response()
+        }
+    }
+
+    async fn get_static_file(uri: Uri, root: &str) -> Result<Response<BoxBody>, (StatusCode, String)> {
+        let req = Request::builder().uri(uri.clone()).body(Body::empty()).unwrap();
+        // `ServeDir` implements `tower::Service` so we can call it with `tower::ServiceExt::oneshot`
+        // This path is relative to the cargo root
+        match ServeDir::new(root).oneshot(req).await {
+            Ok(res) => Ok(res.map(boxed)),
+            Err(err) => Err((
+                StatusCode::INTERNAL_SERVER_ERROR,
+                format!("Something went wrong: {err}"),
+            )),
+        }
+    }
+}}

examples/errors_axum/src/landing.rs

@@ -0,0 +1,86 @@
+use crate::{
+    error_template::{ErrorTemplate, ErrorTemplateProps},
+    errors::AppError,
+};
+use leptos::*;
+use leptos_meta::*;
+use leptos_router::*;
+
+#[cfg(feature = "ssr")]
+pub fn register_server_functions() {
+    _ = CauseInternalServerError::register();
+}
+
+#[server(CauseInternalServerError, "/api")]
+pub async fn cause_internal_server_error() -> Result<(), ServerFnError> {
+    // fake API delay
+    std::thread::sleep(std::time::Duration::from_millis(1250));
+
+    Err(ServerFnError::ServerError(
+        "Generic Server Error".to_string(),
+    ))
+}
+
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+    //let id = use_context::<String>(cx);
+    provide_meta_context(cx);
+    view! {
+        cx,
+        <Link rel="shortcut icon" type_="image/ico" href="/favicon.ico"/>
+        <Stylesheet id="leptos" href="/pkg/errors_axum.css"/>
+        <Router fallback=|cx| {
+            let mut outside_errors = Errors::default();
+            outside_errors.insert_with_default_key(AppError::NotFound);
+            view! { cx,
+                <ErrorTemplate outside_errors/>
+            }
+            .into_view(cx)
+        }>
+            <header>
+                <h1>"Error Examples:"</h1>
+            </header>
+            <main>
+                <Routes>
+                    <Route path="" view=|cx| view! {
+                        cx,
+                        <ExampleErrors/>
+                    }/>
+                </Routes>
+            </main>
+        </Router>
+    }
+}
+
+#[component]
+pub fn ExampleErrors(cx: Scope) -> impl IntoView {
+    let generate_internal_error = create_server_action::<CauseInternalServerError>(cx);
+
+    view! { cx,
+        <p>
+            "These links will load 404 pages since they do not exist. Verify with browser development tools: " <br/>
+            <a href="/404">"This links to a page that does not exist"</a><br/>
+            <a href="/404" target="_blank">"Same link, but in a new tab"</a>
+        </p>
+        <p>
+            "After pressing this button check browser network tools. Can be used even when WASM is blocked:"
+            <ActionForm action=generate_internal_error>
+                <input name="error1" type="submit" value="Generate Internal Server Error"/>
+            </ActionForm>
+        </p>
+        <p>"The following <div> will always contain an error and cause this page to produce status 500. Check browser dev tools. "</p>
+        <div>
+        // note that the error boundries could be placed above in the Router or lower down
+        // in a particular route. The generated errors on the entire page contribue to the
+        // final status code sent by the server when producing ssr pages.
+        <ErrorBoundary fallback=|cx, errors| view!{cx, <ErrorTemplate errors=errors/>}>
+            <ReturnsError/>
+        </ErrorBoundary>
+        </div>
+    }
+}
+
+#[component]
+pub fn ReturnsError(_cx: Scope) -> impl IntoView {
+    Err::<String, AppError>(AppError::InternalServerError)
+}

examples/errors_axum/src/lib.rs

@@ -0,0 +1,25 @@
+use cfg_if::cfg_if;
+use leptos::*;
+pub mod error_template;
+pub mod errors;
+pub mod fallback;
+pub mod landing;
+
+// Needs to be in lib.rs AFAIK because wasm-bindgen needs us to be compiling a lib. I may be wrong.
+cfg_if! {
+    if #[cfg(feature = "hydrate")] {
+        use wasm_bindgen::prelude::wasm_bindgen;
+        use crate::landing::*;
+
+        #[wasm_bindgen]
+        pub fn hydrate() {
+            console_error_panic_hook::set_once();
+            _ = console_log::init_with_level(log::Level::Debug);
+            console_error_panic_hook::set_once();
+
+            leptos::mount_to_body(|cx| {
+                view! { cx,  <App/> }
+            });
+        }
+    }
+}

examples/errors_axum/src/main.rs

@@ -0,0 +1,72 @@
+use cfg_if::cfg_if;
+
+cfg_if! { if #[cfg(feature = "ssr")] {
+    use crate::fallback::file_and_error_handler;
+    use crate::landing::*;
+    use axum::body::Body as AxumBody;
+    use axum::{
+        extract::{Extension, Path},
+        http::Request,
+        response::{IntoResponse, Response},
+        routing::{get, post},
+        Router,
+    };
+    use errors_axum::*;
+    use leptos::*;
+    use leptos_axum::{generate_route_list, LeptosRoutes};
+    use std::sync::Arc;
+}}
+
+//Define a handler to test extractor with state
+#[cfg(feature = "ssr")]
+async fn custom_handler(
+    Path(id): Path<String>,
+    Extension(options): Extension<Arc<LeptosOptions>>,
+    req: Request<AxumBody>,
+) -> Response {
+    let handler = leptos_axum::render_app_to_stream_with_context(
+        (*options).clone(),
+        move |cx| {
+            provide_context(cx, id.clone());
+        },
+        |cx| view! { cx, <App/> },
+    );
+    handler(req).await.into_response()
+}
+
+#[cfg(feature = "ssr")]
+#[tokio::main]
+async fn main() {
+    simple_logger::init_with_level(log::Level::Debug).expect("couldn't initialize logging");
+
+    crate::landing::register_server_functions();
+
+    // Setting this to None means we'll be using cargo-leptos and its env vars
+    let conf = get_configuration(None).await.unwrap();
+    let leptos_options = conf.leptos_options;
+    let addr = leptos_options.site_addr;
+    let routes = generate_route_list(|cx| view! { cx, <App/> }).await;
+
+    // build our application with a route
+    let app = Router::new()
+        .route("/api/*fn_name", post(leptos_axum::handle_server_fns))
+        .route("/special/:id", get(custom_handler))
+        .leptos_routes(leptos_options.clone(), routes, |cx| view! { cx, <App/> })
+        .fallback(file_and_error_handler)
+        .layer(Extension(Arc::new(leptos_options)));
+
+    // run our app with hyper
+    // `axum::Server` is a re-export of `hyper::Server`
+    log!("listening on http://{}", &addr);
+    axum::Server::bind(&addr)
+        .serve(app.into_make_service())
+        .await
+        .unwrap();
+}
+
+// this is if we were using client-only rending with Trunk
+#[cfg(not(feature = "ssr"))]
+pub fn main() {
+    // This example cannot be built as a trunk standalone CSR-only app.
+    //  The server is needed to demonstrate the error statuses.
+}

examples/errors_axum/style.css

@@ -0,0 +1,3 @@
+.pending {
+	color: purple;
+}

examples/fetch/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/fetch/index.html

@@ -9,6 +9,12 @@
 			max-width: 250px;
 			height: auto;
 		}
+
+		.error {
+			border: 1px solid red;
+			color: red;
+			background-color: lightpink;
+		}
 	</style>
 	<body></body>
 </html>

examples/fetch/src/lib.rs

@@ -1,3 +1,4 @@
+use anyhow::Result;
 use leptos::*;
 use serde::{Deserialize, Serialize};
 
@@ -6,18 +7,18 @@ pub struct Cat {
     url: String,
 }
 
-async fn fetch_cats(count: u32) -> Result<Vec<String>, ()> {
+async fn fetch_cats(count: u32) -> Result<Vec<String>> {
     if count > 0 {
+        // make the request
         let res = reqwasm::http::Request::get(&format!(
-            "https://api.thecatapi.com/v1/images/search?limit={}",
-            count
+            "https://api.thecatapi.com/v1/images/search?limit={count}",
         ))
         .send()
-        .await
-        .map_err(|_| ())?
+        .await?
+        // convert it to JSON
         .json::<Vec<Cat>>()
-        .await
-        .map_err(|_| ())?
+        .await?
+        // extract the URL field for each cat
         .into_iter()
         .map(|cat| cat.url)
         .collect::<Vec<_>>();
@@ -29,9 +30,45 @@ async fn fetch_cats(count: u32) -> Result<Vec<String>, ()> {
 
 pub fn fetch_example(cx: Scope) -> impl IntoView {
     let (cat_count, set_cat_count) = create_signal::<u32>(cx, 1);
-    let cats = create_resource(cx, cat_count, |count| fetch_cats(count));
 
-    view! { cx, 
+    // we use local_resource here because
+    // 1) anyhow::Result isn't serializable/deserializable
+    // 2) we're not doing server-side rendering in this example anyway
+    //    (during SSR, create_resource will begin loading on the server and resolve on the client)
+    let cats = create_local_resource(cx, cat_count, fetch_cats);
+
+    let fallback = move |cx, errors: RwSignal<Errors>| {
+        let error_list = move || {
+            errors.with(|errors| {
+                errors
+                    .iter()
+                    .map(|(_, e)| view! { cx, <li>{e.to_string()}</li>})
+                    .collect::<Vec<_>>()
+            })
+        };
+
+        view! { cx,
+            <div class="error">
+                <h2>"Error"</h2>
+                <ul>{error_list}</ul>
+            </div>
+        }
+    };
+
+    // the renderer can handle Option<_> and Result<_> states
+    // by displaying nothing for None if the resource is still loading
+    // and by using the ErrorBoundary fallback to catch Err(_)
+    // so we'll just implement our happy path and let the framework handle the rest
+    let cats_view = move || {
+        cats.with(cx, |data| {
+            data.iter()
+                .flatten()
+                .map(|cat| view! { cx, <img src={cat}/> })
+                .collect::<Vec<_>>()
+        })
+    };
+
+    view! { cx,
         <div>
             <label>
                 "How many cats would you like?"
@@ -43,25 +80,11 @@ pub fn fetch_example(cx: Scope) -> impl IntoView {
                     }
                 />
             </label>
-            <Transition fallback=move || view! { cx, <div>"Loading (Suspense Fallback)..."</div>}>
-                {move || {
-                        cats.read().map(|data| match data {
-                            Err(_) => view! { cx, <pre>"Error"</pre> }.into_view(cx),
-                            Ok(cats) => view! { cx, 
-                                <div>{
-                                    cats.iter()
-                                        .map(|src| {
-                                            view! { cx, 
-                                                <img src={src}/>
-                                            }
-                                        })
-                                        .collect::<Vec<_>>()
-                                }</div>
-                            }.into_view(cx),
-                        })
-                    }
-                }
-            </Transition>
+            <ErrorBoundary fallback>
+                <Transition fallback=move || view! { cx, <div>"Loading (Suspense Fallback)..."</div>}>
+                    {cats_view}
+                </Transition>
+            </ErrorBoundary>
         </div>
     }
 }

examples/gtk/src/main.rs

@@ -6,7 +6,7 @@ const APP_ID: &str = "dev.leptos.Counter";
 
 // Basic GTK app setup from https://gtk-rs.org/gtk4-rs/stable/latest/book/hello_world.html
 fn main() {
-    _ = create_scope(|cx| {
+    _ = create_scope(create_runtime(), |cx| {
         // Create a new application
         let app = Application::builder().application_id(APP_ID).build();
 

examples/hackernews/Cargo.toml

@@ -9,12 +9,14 @@ crate-type = ["cdylib", "rlib"]
 [dependencies]
 anyhow = "1"
 actix-files = { version = "0.6", optional = true }
-actix-web = { version = "4", optional = true, features = ["openssl", "macros"] }
+actix-web = { version = "4", optional = true, features = ["macros"] }
 console_log = "0.2"
 console_error_panic_hook = "0.1"
 futures = "0.3"
 cfg-if = "1"
-leptos = { path = "../../leptos", default-features = false, features = ["serde"] }
+leptos = { path = "../../leptos", default-features = false, features = [
+	"serde",
+] }
 leptos_meta = { path = "../../meta", default-features = false }
 leptos_actix = { path = "../../integrations/actix", default-features = false, optional = true }
 leptos_router = { path = "../../router", default-features = false }
@@ -47,26 +49,26 @@ skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]
 
 [package.metadata.leptos]
 # The name used by wasm-bindgen/cargo-leptos for the JS/WASM bundle. Defaults to the crate name   
-output-name = "hackernews"	
+output-name = "hackernews"
 # The site root folder is where cargo-leptos generate all output. WARNING: all content of this folder will be erased on a rebuild. Use it in your server setup.
 site-root = "target/site"
 # The site-root relative folder where all compiled output (JS, WASM and CSS) is written
 # Defaults to pkg	
-site-pkg-dir = "pkg" 	
+site-pkg-dir = "pkg"
 # [Optional] The source CSS file. If it ends with .sass or .scss then it will be compiled by dart-sass into CSS. The CSS is optimized by Lightning CSS before being written to <site-root>/<site-pkg>/app.css
 style-file = "./style.css"
 # [Optional] Files in the asset-dir will be copied to the site-root directory
 assets-dir = "public"
 # The IP and port (ex: 127.0.0.1:3000) where the server serves the content. Use it in your server setup.
-site-addr = "127.0.0.1:3000"	
+site-addr = "127.0.0.1:3000"
 # The port to use for automatic reload monitoring
-reload-port = 3001	
+reload-port = 3001
 # [Optional] Command to use when running end2end tests. It will run in the end2end dir.
 end2end-cmd = "npx playwright test"
 #  The browserlist query used for optimizing the CSS.
-browserquery = "defaults" 	
+browserquery = "defaults"
 # Set by cargo-leptos watch when building with tha tool. Controls whether autoreload JS will be included in the head
-watch = false 	
+watch = false
 # The environment Leptos will run in, usually either "DEV" or "PROD"
 env = "DEV"
 # The features to use when compiling the bin target
@@ -87,4 +89,4 @@ lib-features = ["hydrate"]
 # If the --no-default-features flag should be used when compiling the lib target
 #
 # Optional. Defaults to false.
-lib-default-features = false
+lib-default-features = false

examples/hackernews/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/hackernews/src/main.rs

@@ -24,7 +24,7 @@ cfg_if! {
             // Setting this to None means we'll be using cargo-leptos and its env vars.
             let conf = get_configuration(None).await.unwrap();
 
-            let addr = conf.leptos_options.site_address.clone();
+            let addr = conf.leptos_options.site_addr.clone();
             // Generate the list of routes in your Leptos App
             let routes = generate_route_list(|cx| view! { cx, <App/> });
 

examples/hackernews/src/routes/nav.rs

@@ -1,4 +1,4 @@
-use leptos::{component, Scope, IntoView, view};
+use leptos::{component, view, IntoView, Scope};
 use leptos_router::*;
 
 #[component]
@@ -6,7 +6,7 @@ pub fn Nav(cx: Scope) -> impl IntoView {
     view! { cx,
         <header class="header">
             <nav class="inner">
-                <A href="/">
+                <A href="/home">
                     <strong>"HN"</strong>
                 </A>
                 <A href="/new">

examples/hackernews/src/routes/stories.rs

@@ -38,7 +38,7 @@ pub fn Stories(cx: Scope) -> impl IntoView {
     let (pending, set_pending) = create_signal(cx, false);
 
     let hide_more_link =
-        move || pending() || stories.read().unwrap_or(None).unwrap_or_default().len() < 28;
+        move || pending() || stories.read(cx).unwrap_or(None).unwrap_or_default().len() < 28;
 
     view! {
         cx,
@@ -82,7 +82,7 @@ pub fn Stories(cx: Scope) -> impl IntoView {
                         fallback=move || view! { cx,  <p>"Loading..."</p> }
                         set_pending=set_pending.into()
                     >
-                        {move || match stories.read() {
+                        {move || match stories.read(cx) {
                             None => None,
                             Some(None) => Some(view! { cx,  <p>"Error loading stories."</p> }.into_any()),
                             Some(Some(stories)) => {
@@ -91,7 +91,7 @@ pub fn Stories(cx: Scope) -> impl IntoView {
                                         <For
                                             each=move || stories.clone()
                                             key=|story| story.id
-                                            view=move |story: api::Story| {
+                                            view=move |cx, story: api::Story| {
                                                 view! { cx,
                                                     <Story story/>
                                                 }

examples/hackernews/src/routes/story.rs

@@ -17,13 +17,13 @@ pub fn Story(cx: Scope) -> impl IntoView {
             }
         },
     );
-    let meta_description = move || story.read().and_then(|story| story.map(|story| story.title)).unwrap_or_else(|| "Loading story...".to_string());
+    let meta_description = move || story.read(cx).and_then(|story| story.map(|story| story.title)).unwrap_or_else(|| "Loading story...".to_string());
 
     view! { cx,
         <>
             <Meta name="description" content=meta_description/>
                 <Suspense fallback=|| view! { cx, "Loading..." }>
-                    {move || story.read().map(|story| match story {
+                    {move || story.read(cx).map(|story| match story {
                         None => view! { cx,  <div class="item-view">"Error loading this story."</div> },
                         Some(story) => view! { cx,
                             <div class="item-view">
@@ -53,7 +53,7 @@ pub fn Story(cx: Scope) -> impl IntoView {
                                     <For
                                         each=move || story.comments.clone().unwrap_or_default()
                                         key=|comment| comment.id
-                                        view=move |comment| view! { cx,  <Comment comment /> }
+                                        view=move |cx, comment| view! { cx,  <Comment comment /> }
                                     />
                                 </ul>
                             </div>
@@ -98,7 +98,7 @@ pub fn Comment(cx: Scope, comment: api::Comment) -> impl IntoView {
                                 <For
                                     each=move || comments.clone()
                                     key=|comment| comment.id
-                                    view=move |comment: api::Comment| view! { cx, <Comment comment /> }
+                                    view=move |cx, comment: api::Comment| view! { cx, <Comment comment /> }
                                 />
                             </ul>
                         }

examples/hackernews/src/routes/users.rs

@@ -19,7 +19,7 @@ pub fn User(cx: Scope) -> impl IntoView {
     view! { cx,
         <div class="user-view">
             <Suspense fallback=|| view! { cx, "Loading..." }>
-                {move || user.read().map(|user| match user {
+                {move || user.read(cx).map(|user| match user {
                     None => view! { cx,  <h1>"User not found."</h1> }.into_any(),
                     Some(user) => view! { cx,
                         <div>

examples/hackernews_axum/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/hackernews_axum/index.html

@@ -2,7 +2,7 @@
 <html>
 	<head>
 		<link data-trunk rel="rust" data-wasm-opt="z"/>
-		<link data-trunk rel="css" href="./static/style.css"/>
+		<link data-trunk rel="css" href="/style.css"/>
 	</head>
 	<body></body>
 </html>

examples/hackernews_axum/src/error_template.rs

@@ -1,5 +1,7 @@
-use leptos::Errors;
-use leptos::{view, For, ForProps, IntoView, RwSignal, Scope, View};
+use leptos::{
+    signal_prelude::*, view, Errors, For, ForProps, IntoView, RwSignal, Scope,
+    View,
+};
 
 // A basic function to display errors served by the error boundaries. Feel free to do more complicated things
 // here than just displaying them
@@ -7,21 +9,22 @@ pub fn error_template(cx: Scope, errors: Option<RwSignal<Errors>>) -> View {
     let Some(errors) = errors else {
         panic!("No Errors found and we expected errors!");
     };
+
     view! {cx,
-    <h1>"Errors"</h1>
-    <For
-        // a function that returns the items we're iterating over; a signal is fine
-        each= move || {errors.get().0.into_iter()}
-        // a unique key for each item as a reference
-        key=|error| error.0.clone()
-        // renders each item to a view
-        view= move |error| {
-        let error_string = error.1.to_string();
-          view! {
-            cx,
-            <p>"Error: " {error_string}</p>
+      <h1>"Errors"</h1>
+      <For
+          // a function that returns the items we're iterating over; a signal is fine
+          each=errors
+          // a unique key for each item as a reference
+          key=|(key, _)| key.clone()
+          // renders each item to a view
+          view= move |cx, (_, error)| {
+          let error_string = error.to_string();
+            view! {
+              cx,
+              <p>"Error: " {error_string}</p>
+            }
           }
-        }
       />
     }
     .into_view(cx)

examples/hackernews_axum/src/main.rs

@@ -19,7 +19,7 @@ if #[cfg(feature = "ssr")] {
 
         let conf = get_configuration(Some("Cargo.toml")).await.unwrap();
         let leptos_options = conf.leptos_options;
-        let addr = leptos_options.site_address.clone();
+        let addr = leptos_options.site_addr.clone();
         let routes = generate_route_list(|cx| view! { cx, <App/> }).await;
 
         simple_logger::init_with_level(log::Level::Debug).expect("couldn't initialize logging");

examples/hackernews_axum/src/routes/stories.rs

@@ -38,7 +38,7 @@ pub fn Stories(cx: Scope) -> impl IntoView {
     let (pending, set_pending) = create_signal(cx, false);
 
     let hide_more_link =
-        move || pending() || stories.read().unwrap_or(None).unwrap_or_default().len() < 28;
+        move || pending() || stories.read(cx).unwrap_or(None).unwrap_or_default().len() < 28;
 
     view! {
         cx,
@@ -82,7 +82,7 @@ pub fn Stories(cx: Scope) -> impl IntoView {
                         fallback=move || view! { cx,  <p>"Loading..."</p> }
                         set_pending=set_pending.into()
                     >
-                        {move || match stories.read() {
+                        {move || match stories.read(cx) {
                             None => None,
                             Some(None) => Some(view! { cx,  <p>"Error loading stories."</p> }.into_any()),
                             Some(Some(stories)) => {
@@ -91,7 +91,7 @@ pub fn Stories(cx: Scope) -> impl IntoView {
                                         <For
                                             each=move || stories.clone()
                                             key=|story| story.id
-                                            view=move |story: api::Story| {
+                                            view=move |cx, story: api::Story| {
                                                 view! { cx,
                                                     <Story story/>
                                                 }

examples/hackernews_axum/src/routes/story.rs

@@ -17,13 +17,13 @@ pub fn Story(cx: Scope) -> impl IntoView {
             }
         },
     );
-    let meta_description = move || story.read().and_then(|story| story.map(|story| story.title)).unwrap_or_else(|| "Loading story...".to_string());
+    let meta_description = move || story.read(cx).and_then(|story| story.map(|story| story.title)).unwrap_or_else(|| "Loading story...".to_string());
 
     view! { cx,
         <>
             <Meta name="description" content=meta_description/>
                 <Suspense fallback=|| view! { cx, "Loading..." }>
-                    {move || story.read().map(|story| match story {
+                    {move || story.read(cx).map(|story| match story {
                         None => view! { cx,  <div class="item-view">"Error loading this story."</div> },
                         Some(story) => view! { cx,
                             <div class="item-view">
@@ -53,7 +53,7 @@ pub fn Story(cx: Scope) -> impl IntoView {
                                     <For
                                         each=move || story.comments.clone().unwrap_or_default()
                                         key=|comment| comment.id
-                                        view=move |comment| view! { cx,  <Comment comment /> }
+                                        view=move |cx, comment| view! { cx,  <Comment comment /> }
                                     />
                                 </ul>
                             </div>
@@ -98,7 +98,7 @@ pub fn Comment(cx: Scope, comment: api::Comment) -> impl IntoView {
                                 <For
                                     each=move || comments.clone()
                                     key=|comment| comment.id
-                                    view=move |comment: api::Comment| view! { cx, <Comment comment /> }
+                                    view=move |cx, comment: api::Comment| view! { cx, <Comment comment /> }
                                 />
                             </ul>
                         }

examples/hackernews_axum/src/routes/users.rs

@@ -19,7 +19,7 @@ pub fn User(cx: Scope) -> impl IntoView {
     view! { cx,
         <div class="user-view">
             <Suspense fallback=|| view! { cx, "Loading..." }>
-                {move || user.read().map(|user| match user {
+                {move || user.read(cx).map(|user| match user {
                     None => view! { cx,  <h1>"User not found."</h1> }.into_any(),
                     Some(user) => view! { cx,
                         <div>

examples/parent_child/Cargo.toml

@@ -8,4 +8,4 @@ leptos = { path = "../../leptos" }
 console_log = "0.2"
 log = "0.4"
 console_error_panic_hook = "0.1.7"
-
+web-sys = "0.3"

examples/parent_child/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/parent_child/README.md

@@ -2,12 +2,12 @@
 
 This example highlights four different ways that child components can communicate with their parent:
 
-1. <ButtonA/>: passing a WriteSignal as one of the child component props,
+1. `<ButtonA/>`: passing a WriteSignal as one of the child component props,
    for the child component to write into and the parent to read
-2. <ButtonB/>: passing a closure as one of the child component props, for
+2. `<ButtonB/>`: passing a closure as one of the child component props, for
    the child component to call
-3. <ButtonC/>: adding a simple event listener on the child component itself
-4. <ButtonD/>: providing a context that is used in the component (rather than prop drilling)
+3. `<ButtonC/>`: adding a simple event listener on the child component itself
+4. `<ButtonD/>`: providing a context that is used in the component (rather than prop drilling)
 
 ## Client Side Rendering
 

examples/parent_child/src/lib.rs

@@ -7,7 +7,8 @@ use web_sys::MouseEvent;
 //    for the child component to write into and the parent to read
 // 2) <ButtonB/>: passing a closure as one of the child component props, for
 //    the child component to call
-// 4) <ButtonC/>: providing a context that is used in the component (rather than prop drilling)
+// 3) <ButtonC/>: adding an `on:` event listener to a component
+// 4) <ButtonD/>: providing a context that is used in the component (rather than prop drilling)
 
 #[derive(Copy, Clone)]
 struct SmallcapsContext(WriteSignal<bool>);
@@ -17,6 +18,7 @@ pub fn App(cx: Scope) -> impl IntoView {
     // just some signals to toggle three classes on our <p>
     let (red, set_red) = create_signal(cx, false);
     let (right, set_right) = create_signal(cx, false);
+    let (italics, set_italics) = create_signal(cx, false);
     let (smallcaps, set_smallcaps) = create_signal(cx, false);
 
     // the newtype pattern isn't *necessary* here but is a good practice
@@ -31,6 +33,7 @@ pub fn App(cx: Scope) -> impl IntoView {
                 // class: attributes take F: Fn() => bool, and these signals all implement Fn()
                 class:red=red
                 class:right=right
+                class:italics=italics
                 class:smallcaps=smallcaps
             >
                 "Lorem ipsum sit dolor amet."
@@ -42,8 +45,13 @@ pub fn App(cx: Scope) -> impl IntoView {
             // Button B: pass a closure
             <ButtonB on_click=move |_| set_right.update(|value| *value = !*value)/>
 
+            // Button B: use a regular event listener
+            // setting an event listener on a component like this applies it
+            // to each of the top-level elements the component returns
+            <ButtonC on:click=move |_| set_italics.update(|value| *value = !*value)/>
+
             // Button D gets its setter from context rather than props
-            <ButtonC/>
+            <ButtonD/>
         </main>
     }
 }
@@ -53,7 +61,7 @@ pub fn App(cx: Scope) -> impl IntoView {
 pub fn ButtonA(
     cx: Scope,
     /// Signal that will be toggled when the button is clicked.
-    setter: WriteSignal<bool>
+    setter: WriteSignal<bool>,
 ) -> impl IntoView {
     view! {
         cx,
@@ -70,7 +78,7 @@ pub fn ButtonA(
 pub fn ButtonB<F>(
     cx: Scope,
     /// Callback that will be invoked when the button is clicked.
-    on_click: F
+    on_click: F,
 ) -> impl IntoView
 where
     F: Fn(MouseEvent) + 'static,
@@ -97,10 +105,22 @@ where
     // if Rust ever had named function arguments we could drop this requirement
 }
 
+/// Button C is a dummy: it renders a button but doesn't handle
+/// its click. Instead, the parent component adds an event listener.
+#[component]
+pub fn ButtonC(cx: Scope) -> impl IntoView {
+    view! {
+        cx,
+        <button>
+            "Toggle Italics"
+        </button>
+    }
+}
+
 /// Button D is very similar to Button A, but instead of passing the setter as a prop
 /// we get it from the context
 #[component]
-pub fn ButtonC(cx: Scope) -> impl IntoView {
+pub fn ButtonD(cx: Scope) -> impl IntoView {
     let setter = use_context::<SmallcapsContext>(cx).unwrap().0;
 
     view! {

examples/router/Makefile.toml

@@ -2,3 +2,8 @@
 command = "cargo"
 args = ["+nightly", "build-all-features"]
 install_crate = "cargo-all-features"
+
+[tasks.check]
+command = "cargo"
+args = ["+nightly", "check-all-features"]
+install_crate = "cargo-all-features"

examples/router/src/lib.rs

@@ -1,14 +1,18 @@
 mod api;
-
+use crate::api::*;
 use leptos::*;
 use leptos_router::*;
 
-use crate::api::{get_contact, get_contacts};
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+struct ExampleContext(i32);
 
 #[component]
 pub fn RouterExample(cx: Scope) -> impl IntoView {
     log::debug!("rendering <RouterExample/>");
 
+    // contexts are passed down through the route tree
+    provide_context(cx, ExampleContext(0));
+
     view! { cx,
         <Router>
             <nav>
@@ -20,6 +24,7 @@ pub fn RouterExample(cx: Scope) -> impl IntoView {
                 <A exact=true href="/">"Contacts"</A>
                 <A href="about">"About"</A>
                 <A href="settings">"Settings"</A>
+                <A href="redirect-home">"Redirect to Home"</A>
             </nav>
             <main>
                 <Routes>
@@ -44,6 +49,10 @@ pub fn RouterExample(cx: Scope) -> impl IntoView {
                         path="settings"
                         view=move |cx| view! { cx,  <Settings/> }
                     />
+                    <Route
+                        path="redirect-home"
+                        view=move |cx| view! { cx, <Redirect path="/"/> }
+                    />
                 </Routes>
             </main>
         </Router>
@@ -54,10 +63,18 @@ pub fn RouterExample(cx: Scope) -> impl IntoView {
 pub fn ContactList(cx: Scope) -> impl IntoView {
     log::debug!("rendering <ContactList/>");
 
+    // contexts are passed down through the route tree
+    provide_context(cx, ExampleContext(42));
+
+    on_cleanup(cx, || {
+        log!("cleaning up <ContactList/>");
+    });
+
     let location = use_location(cx);
-    let contacts = create_resource(cx, move || location.search.get(), get_contacts);
+    let contacts =
+        create_resource(cx, move || location.search.get(), get_contacts);
     let contacts = move || {
-        contacts.read().map(|contacts| {
+        contacts.read(cx).map(|contacts| {
             // this data doesn't change frequently so we can use .map().collect() instead of a keyed <For/>
             contacts
                 .into_iter()
@@ -81,21 +98,28 @@ pub fn ContactList(cx: Scope) -> impl IntoView {
     }
 }
 
+#[derive(Params, PartialEq, Clone, Debug)]
+pub struct ContactParams {
+    id: usize,
+}
+
 #[component]
 pub fn Contact(cx: Scope) -> impl IntoView {
     log::debug!("rendering <Contact/>");
 
-    let params = use_params_map(cx);
+    log::debug!(
+        "ExampleContext should be Some(42). It is {:?}",
+        use_context::<ExampleContext>(cx)
+    );
+
+    on_cleanup(cx, || {
+        log!("cleaning up <Contact/>");
+    });
+
+    let params = use_params::<ContactParams>(cx);
     let contact = create_resource(
         cx,
-        move || {
-            params()
-                .get("id")
-                .cloned()
-                .unwrap_or_default()
-                .parse::<usize>()
-                .ok()
-        },
+        move || params().map(|params| params.id).ok(),
         // any of the following would work (they're identical)
         // move |id| async move { get_contact(id).await }
         // move |id| get_contact(id),
@@ -103,12 +127,15 @@ pub fn Contact(cx: Scope) -> impl IntoView {
         get_contact,
     );
 
-    let contact_display = move || match contact.read() {
+    let contact_display = move || match contact.read(cx) {
         // None => loading, but will be caught by Suspense fallback
         // I'm only doing this explicitly for the example
         None => None,
         // Some(None) => has loaded and found no contact
-        Some(None) => Some(view! { cx, <p>"No contact with this ID was found."</p> }.into_any()),
+        Some(None) => Some(
+            view! { cx, <p>"No contact with this ID was found."</p> }
+                .into_any(),
+        ),
         // Some(Some) => has loaded and found a contact
         Some(Some(contact)) => Some(
             view! { cx,
@@ -133,6 +160,16 @@ pub fn Contact(cx: Scope) -> impl IntoView {
 #[component]
 pub fn About(cx: Scope) -> impl IntoView {
     log::debug!("rendering <About/>");
+
+    on_cleanup(cx, || {
+        log!("cleaning up <About/>");
+    });
+
+    log::debug!(
+        "ExampleContext should be Some(0). It is {:?}",
+        use_context::<ExampleContext>(cx)
+    );
+
     // use_navigate allows you to navigate programmatically by calling a function
     let navigate = use_navigate(cx);
 
@@ -154,6 +191,11 @@ pub fn About(cx: Scope) -> impl IntoView {
 #[component]
 pub fn Settings(cx: Scope) -> impl IntoView {
     log::debug!("rendering <Settings/>");
+
+    on_cleanup(cx, || {
+        log!("cleaning up <Settings/>");
+    });
+
     view! { cx,
         <>
             <h1>"Settings"</h1>

examples/ssr_modes/.gitignore

@@ -0,0 +1,13 @@
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+pkg
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# node e2e test tools and outputs
+node_modules/
+test-results/
+end2end/playwright-report/
+playwright/.cache/

examples/ssr_modes/Cargo.toml

@@ -0,0 +1,88 @@
+[package]
+name = "ssr_modes"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+actix-files = { version = "0.6", optional = true }
+actix-web = { version = "4", optional = true, features = ["macros"] }
+console_error_panic_hook = "0.1"
+console_log = "0.2"
+cfg-if = "1"
+lazy_static = "1"
+leptos = { path = "../../leptos", default-features = false, features = [
+  "serde",
+] }
+leptos_meta = { path = "../../meta", default-features = false }
+leptos_actix = { path = "../../integrations/actix", default-features = false, optional = true }
+leptos_router = { path = "../../router", default-features = false }
+log = "0.4"
+serde = { version = "1", features = ["derive"] }
+simple_logger = "4"
+thiserror = "1"
+tokio = { version = "1", features = ["time"] }
+wasm-bindgen = "0.2"
+
+[features]
+hydrate = ["leptos/hydrate", "leptos_meta/hydrate", "leptos_router/hydrate"]
+ssr = [
+  "dep:actix-files",
+  "dep:actix-web",
+  "dep:leptos_actix",
+  "leptos/ssr",
+  "leptos_meta/ssr",
+  "leptos_router/ssr",
+]
+
+[package.metadata.leptos]
+# The name used by wasm-bindgen/cargo-leptos for the JS/WASM bundle. Defaults to the crate name   
+output-name = "ssr_modes"
+# The site root folder is where cargo-leptos generate all output. WARNING: all content of this folder will be erased on a rebuild. Use it in your server setup.
+site-root = "target/site"
+# The site-root relative folder where all compiled output (JS, WASM and CSS) is written
+# Defaults to pkg	
+site-pkg-dir = "pkg"
+# [Optional] The source CSS file. If it ends with .sass or .scss then it will be compiled by dart-sass into CSS. The CSS is optimized by Lightning CSS before being written to <site-root>/<site-pkg>/app.css
+style-file = "style/main.scss"
+# Assets source dir. All files found here will be copied and synchronized to site-root.
+# The assets-dir cannot have a sub directory with the same name/path as site-pkg-dir.
+#
+# Optional. Env: LEPTOS_ASSETS_DIR.
+assets-dir = "assets"
+# The IP and port (ex: 127.0.0.1:3000) where the server serves the content. Use it in your server setup.
+site-addr = "127.0.0.1:3000"
+# The port to use for automatic reload monitoring
+reload-port = 3001
+# [Optional] Command to use when running end2end tests. It will run in the end2end dir.
+#   [Windows] for non-WSL use "npx.cmd playwright test"
+#   This binary name can be checked in Powershell with Get-Command npx
+end2end-cmd = "npx playwright test"
+end2end-dir = "end2end"
+#  The browserlist query used for optimizing the CSS.
+browserquery = "defaults"
+# Set by cargo-leptos watch when building with that tool. Controls whether autoreload JS will be included in the head
+watch = false
+# The environment Leptos will run in, usually either "DEV" or "PROD"
+env = "DEV"
+# The features to use when compiling the bin target
+#
+# Optional. Can be over-ridden with the command line parameter --bin-features
+bin-features = ["ssr"]
+
+# If the --no-default-features flag should be used when compiling the bin target
+#
+# Optional. Defaults to false.
+bin-default-features = false
+
+# The features to use when compiling the lib target
+#
+# Optional. Can be over-ridden with the command line parameter --lib-features
+lib-features = ["hydrate"]
+
+# If the --no-default-features flag should be used when compiling the lib target
+#
+# Optional. Defaults to false.
+lib-default-features = false

examples/ssr_modes/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 henrik
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

examples/ssr_modes/README.md

@@ -0,0 +1,54 @@
+# Server-Side Rendering Modes
+
+This example shows the different "rendering modes" that can be used while server-side 
+rendering an application:
+1. **Synchronous**: Serve an HTML shell that includes `fallback` for any `Suspense`. Load data on the client, replacing `fallback` once they're loaded.
+     - *Pros*: App shell appears very quickly: great TTFB (time to first byte).
+     - *Cons*: Resources load relatively slowly; you need to wait for JS + Wasm to load before even making a request.
+ 2. **Out-of-order streaming**: Serve an HTML shell that includes `fallback` for any `Suspense`. Load data on the **server**, streaming it down to the client as it resolves, and streaming down HTML for `Suspense` nodes.
+     - *Pros*: Combines the best of **synchronous** and **`async`**, with a very fast shell and resources that begin loading on the server.
+     - *Cons*: Requires JS for suspended fragments to appear in correct order. Weaker meta tag support when it depends on data that's under suspense (has already streamed down `<head>`)
+ 3. **In-order streaming**: Walk through the tree, returning HTML synchronously as in synchronous rendering and out-of-order streaming until you hit a `Suspense`. At that point, wait for all its data to load, then render it, then the rest of the tree.
+     - *Pros*: Does not require JS for HTML to appear in correct order.
+     - *Cons*: Loads the shell more slowly than out-of-order streaming or synchronous rendering because it needs to pause at every `Suspense`. Cannot begin hydration until the entire page has loaded, so earlier pieces
+       of the page will not be interactive until the suspended chunks have loaded.
+ 4. **`async`**: Load all resources on the server. Wait until all data are loaded, and render HTML in one sweep.
+     - *Pros*: Better handling for meta tags (because you know async data even before you render the `<head>`). Faster complete load than **synchronous** because async resources begin loading on server.
+     - *Cons*: Slower load time/TTFB: you need to wait for all async resources to load before displaying anything on the client.
+
+## Server Side Rendering with `cargo-leptos`
+`cargo-leptos` is now the easiest and most featureful way to build server side rendered apps with hydration. It provides automatic recompilation of client and server code, wasm optimisation, CSS minification, and more! Check out more about it [here](https://github.com/akesson/cargo-leptos)
+
+1. Install cargo-leptos
+```bash
+cargo install --locked cargo-leptos
+``` 
+2. Build the site in watch mode, recompiling on file changes
+```bash
+cargo leptos watch
+```
+
+Open browser on [http://localhost:3000/](http://localhost:3000/)
+
+3. When ready to deploy, run
+```bash
+cargo leptos build --release
+```
+
+## Server Side Rendering without cargo-leptos
+To run it as a server side app with hydration, you'll need to have wasm-pack installed.
+
+0. Edit the `[package.metadata.leptos]` section and set `site-root` to `"."`. You'll also want to change the path of the `<StyleSheet / >` component in the root component to point towards the CSS file in the root. This tells leptos that the WASM/JS files generated by wasm-pack are available at `./pkg` and that the CSS files are no longer processed by cargo-leptos. Building to alternative folders is not supported at this time. You'll also want to edit the call to `get_configuration()` to pass in `Some(Cargo.toml)`, so that Leptos will read the settings instead of cargo-leptos. If you do so, your file/folder names cannot include dashes.
+1. Install wasm-pack
+```bash
+cargo install wasm-pack
+```
+2. Build the Webassembly used to hydrate the HTML from the server
+```bash
+wasm-pack build --target=web --debug --no-default-features --features=hydrate
+```
+3. Run the server to serve the Webassembly, JS, and HTML 
+```bash
+cargo run --no-default-features --features=ssr
+```
+

examples/ssr_modes/src/app.rs

@@ -0,0 +1,184 @@
+use lazy_static::lazy_static;
+use leptos::*;
+use leptos_meta::*;
+use leptos_router::*;
+use serde::{Deserialize, Serialize};
+use thiserror::Error;
+
+#[component]
+pub fn App(cx: Scope) -> impl IntoView {
+    // Provides context that manages stylesheets, titles, meta tags, etc.
+    provide_meta_context(cx);
+
+    view! { cx,
+        <Stylesheet id="leptos" href="/pkg/ssr_modes.css"/>
+        <Title text="Welcome to Leptos"/>
+
+        <Router>
+            <main>
+                <Routes>
+                    // We’ll load the home page with out-of-order streaming and <Suspense/>
+                    <Route path="" view=|cx| view! { cx, <HomePage/> }/>
+
+                    // We'll load the posts with async rendering, so they can set
+                    // the title and metadata *after* loading the data
+                    <Route
+                        path="/post/:id"
+                        view=|cx| view! { cx, <Post/> }
+                        ssr=SsrMode::Async
+                    />
+                </Routes>
+            </main>
+        </Router>
+    }
+}
+
+#[component]
+fn HomePage(cx: Scope) -> impl IntoView {
+    // load the posts
+    let posts =
+        create_resource(cx, || (), |_| async { list_post_metadata().await });
+    let posts_view = move || {
+        posts.with(cx, |posts| posts
+            .clone()
+            .map(|posts| {
+                posts.iter()
+                .map(|post| view! { cx, <li><a href=format!("/post/{}", post.id)>{&post.title}</a></li>})
+                .collect::<Vec<_>>()
+            })
+        )
+    };
+
+    view! { cx,
+        <h1>"My Great Blog"</h1>
+        <Suspense fallback=move || view! { cx, <p>"Loading posts..."</p> }>
+            <ul>{posts_view}</ul>
+        </Suspense>
+    }
+}
+
+#[derive(Params, Copy, Clone, Debug, PartialEq, Eq)]
+pub struct PostParams {
+    id: usize,
+}
+
+#[component]
+fn Post(cx: Scope) -> impl IntoView {
+    let query = use_params::<PostParams>(cx);
+    let id = move || {
+        query.with(|q| {
+            q.as_ref().map(|q| q.id).map_err(|_| PostError::InvalidId)
+        })
+    };
+    let post = create_resource(cx, id, |id| async move {
+        match id {
+            Err(e) => Err(e),
+            Ok(id) => get_post(id)
+                .await
+                .map(|data| data.ok_or(PostError::PostNotFound))
+                .map_err(|_| PostError::ServerError)
+                .flatten(),
+        }
+    });
+
+    let post_view = move || {
+        post.with(cx, |post| {
+            post.clone().map(|post| {
+                view! { cx,
+                    // render content
+                    <h1>{&post.title}</h1>
+                    <p>{&post.content}</p>
+
+                    // since we're using async rendering for this page,
+                    // this metadata should be included in the actual HTML <head>
+                    // when it's first served
+                    <Title text=post.title/>
+                    <Meta name="description" content=post.content/>
+                }
+            })
+        })
+    };
+
+    view! { cx,
+        <Suspense fallback=move || view! { cx, <p>"Loading post..."</p> }>
+            <ErrorBoundary fallback=|cx, errors| {
+                view! { cx,
+                    <div class="error">
+                        <h1>"Something went wrong."</h1>
+                        <ul>
+                        {move || errors.get()
+                            .into_iter()
+                            .map(|(_, error)| view! { cx, <li>{error.to_string()} </li> })
+                            .collect::<Vec<_>>()
+                        }
+                        </ul>
+                    </div>
+                }
+            }>
+                {post_view}
+            </ErrorBoundary>
+        </Suspense>
+    }
+}
+
+// Dummy API
+lazy_static! {
+    static ref POSTS: Vec<Post> = vec![
+        Post {
+            id: 0,
+            title: "My first post".to_string(),
+            content: "This is my first post".to_string(),
+        },
+        Post {
+            id: 1,
+            title: "My second post".to_string(),
+            content: "This is my second post".to_string(),
+        },
+        Post {
+            id: 2,
+            title: "My third post".to_string(),
+            content: "This is my third post".to_string(),
+        },
+    ];
+}
+
+#[derive(Error, Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub enum PostError {
+    #[error("Invalid post ID.")]
+    InvalidId,
+    #[error("Post not found.")]
+    PostNotFound,
+    #[error("Server error.")]
+    ServerError,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Post {
+    id: usize,
+    title: String,
+    content: String,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct PostMetadata {
+    id: usize,
+    title: String,
+}
+
+#[server(ListPostMetadata, "/api")]
+pub async fn list_post_metadata() -> Result<Vec<PostMetadata>, ServerFnError> {
+    tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+    Ok(POSTS
+        .iter()
+        .map(|data| PostMetadata {
+            id: data.id,
+            title: data.title.clone(),
+        })
+        .collect())
+}
+
+#[server(GetPost, "/api")]
+pub async fn get_post(id: usize) -> Result<Option<Post>, ServerFnError> {
+    tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+    Ok(POSTS.iter().find(|post| post.id == id).cloned())
+}

examples/ssr_modes/src/lib.rs

@@ -0,0 +1,25 @@
+#![feature(result_flattening)]
+
+pub mod app;
+use cfg_if::cfg_if;
+
+cfg_if! {
+if #[cfg(feature = "hydrate")] {
+
+  use wasm_bindgen::prelude::wasm_bindgen;
+
+    #[wasm_bindgen]
+    pub fn hydrate() {
+      use app::*;
+      use leptos::*;
+
+      // initializes logging using the `log` crate
+      _ = console_log::init_with_level(log::Level::Debug);
+      console_error_panic_hook::set_once();
+
+      leptos::mount_to_body(move |cx| {
+          view! { cx, <App/> }
+      });
+    }
+}
+}

examples/ssr_modes/src/main.rs

@@ -0,0 +1,42 @@
+#[cfg(feature = "ssr")]
+#[actix_web::main]
+async fn main() -> std::io::Result<()> {
+    use actix_files::Files;
+    use actix_web::*;
+    use leptos::*;
+    use leptos_actix::{generate_route_list, LeptosRoutes};
+    use ssr_modes::app::*;
+
+    let conf = get_configuration(None).await.unwrap();
+    let addr = conf.leptos_options.site_addr;
+    // Generate the list of routes in your Leptos App
+    let routes = generate_route_list(|cx| view! { cx, <App/> });
+
+    GetPost::register();
+    ListPostMetadata::register();
+
+    HttpServer::new(move || {
+        let leptos_options = &conf.leptos_options;
+        let site_root = &leptos_options.site_root;
+
+        App::new()
+            .route("/api/{tail:.*}", leptos_actix::handle_server_fns())
+            .leptos_routes(
+                leptos_options.to_owned(),
+                routes.to_owned(),
+                |cx| view! { cx, <App/> },
+            )
+            .service(Files::new("/", site_root))
+        //.wrap(middleware::Compress::default())
+    })
+    .bind(&addr)?
+    .run()
+    .await
+}
+
+#[cfg(not(feature = "ssr"))]
+pub fn main() {
+    // no client-side main function
+    // unless we want this to work with e.g., Trunk for pure client-side testing
+    // see lib.rs for hydration function instead
+}