Fix warning for unused variable.

Adjust tracing

.github/workflows/test.yml

@@ -21,7 +21,7 @@ jobs:
           - ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Setup Rust
         uses: actions-rs/toolchain@v1

Cargo.toml

@@ -23,10 +23,23 @@ members = [
 ]
 exclude = ["benchmarks", "examples"]
 
+[workspace.package]
+version = "0.1.0-beta"
+
+[workspace.dependencies]
+leptos = { path = "./leptos", default-features = false, version = "0.1.0-beta" }
+leptos_dom = { path = "./leptos_dom", default-features = false, version = "0.1.0-beta" }
+leptos_macro = { path = "./leptos_macro", default-features = false, version = "0.1.0-beta" }
+leptos_reactive = { path = "./leptos_reactive", default-features = false, version = "0.1.0-beta" }
+leptos_server = { path = "./leptos_server", default-features = false, version = "0.1.0-beta" }
+leptos_config = { path = "./leptos_config", default-features = false, version = "0.1.0-beta" }
+leptos_router = { path = "./router", version = "0.1.0-beta" }
+leptos_meta = { path = "./meta", default-feature = false, version = "0.1.0-beta" }
+
 [profile.release]
 codegen-units = 1
 lto = true
 opt-level = 'z'
 
 [workspace.metadata.cargo-all-features]
-skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]
+skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]

examples/counter_isomorphic/Cargo.toml

@@ -28,7 +28,6 @@ gloo-net = { git = "https://github.com/rustwasm/gloo" }
 
 [features]
 default = []
-csr = ["leptos/csr", "leptos_meta/csr", "leptos_router/csr"]
 hydrate = ["leptos/hydrate", "leptos_meta/hydrate", "leptos_router/hydrate"]
 ssr = [
 	"dep:actix-files",
@@ -41,31 +40,31 @@ ssr = [
 stable = ["leptos/stable", "leptos_router/stable"]
 
 [package.metadata.cargo-all-features]
-denylist = ["actix-files", "actix-web", "leptos_actix"]
-skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]
+denylist = ["actix-files", "actix-web", "leptos_actix", "stable"]
+skip_feature_sets = [["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 = "counter_isomorphic"	
+output-name = "counter_isomorphic"
 # 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 = "src/styles/tailwind.css"
 # [Optional] Files in the asset-dir will be copied to the site-root directory
 # assets-dir = "static/assets"
 # The IP and port (ex: 127.0.0.1:3000) where the server serves the content. Use it in your server setup.
-site-address = "127.0.0.1:3000"	
+site-address = "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
@@ -86,4 +85,4 @@ 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/src/lib.rs

@@ -15,7 +15,7 @@ pub fn App(cx: Scope) -> impl IntoView {
     view! {
         cx,
         <>
-            <Stylesheet id="leptos" href="./target/site/pkg/hackernews.css"/>
+            <Stylesheet id="leptos" href="/target/site/pkg/hackernews.css"/>
             <Meta name="description" content="Leptos implementation of a HackerNews demo."/>
             <Router>
                 <Nav />

examples/router/Cargo.toml

@@ -7,11 +7,11 @@ edition = "2021"
 console_log = "0.2"
 log = "0.4"
 leptos = { path = "../../leptos" }
-leptos_router = { path = "../../router", features=["csr"] }
+leptos_router = { path = "../../router", features = ["csr"] }
 serde = { version = "1", features = ["derive"] }
 futures = "0.3"
 console_error_panic_hook = "0.1.7"
-leptos_meta = { path = "../../meta", default-features = false }
+leptos_meta = { path = "../../meta", features = ["csr"] }
 
 [dev-dependencies]
 wasm-bindgen-test = "0.3.0"

integrations/actix/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos_actix"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -10,13 +10,7 @@ description = "Actix integrations for the Leptos web framework."
 [dependencies]
 actix-web = "4"
 futures = "0.3"
-leptos = { path = "../../leptos", default-features = false, version = "0.1.0-alpha", features = [
-	"ssr",
-] }
-leptos_meta = { path = "../../meta", default-features = false, version = "0.1.0-alpha", features = [
-	"ssr",
-] }
-leptos_router = { path = "../../router", default-features = false, version = "0.1.0-alpha", features = [
-	"ssr",
-] }
+leptos = { workspace = true, features = ["ssr"] }
+leptos_meta = { workspace = true, features = ["ssr"] }
+leptos_router = { workspace = true, features = ["ssr"] }
 tokio = { version = "1.0", features = ["full"] }

integrations/actix/src/lib.rs

@@ -290,7 +290,7 @@ where IV: IntoView
                 // the site was built with cargo run and not cargo-leptos
                 let bundle_path = match site_root.as_ref() {
                     "pkg" => "pkg".to_string(),
-                    _ => format!("{}/{}", site_root, pkg_path),
+                    _ => format!("{site_root}/{pkg_path}"),
                 };
              
                 let leptos_autoreload = match std::env::var("LEPTOS_WATCH").is_ok() {
@@ -358,7 +358,7 @@ where IV: IntoView
 
             let res_options = res_options.0.read().await;
 
-            let (status, mut headers) = (res_options.status.clone(), res_options.headers.clone());
+            let (status, mut headers) = (res_options.status, res_options.headers.clone());
             let status = status.unwrap_or_default();
             
             let complete_stream =

integrations/axum/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos_axum"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -8,20 +8,14 @@ repository = "https://github.com/gbj/leptos"
 description = "Axum integrations for the Leptos web framework."
 
 [dependencies]
-axum = {version="0.6", features=["macros"]}
+axum = { version = "0.6", features = ["macros"] }
 derive_builder = "0.12.0"
 futures = "0.3"
 http = "0.2.8"
 hyper = "0.14.23"
 kdl = "4.6.0"
-leptos = { path = "../../leptos", default-features = false, version = "0.1.0-beta", features = [
-	"ssr",
-] }
-leptos_meta = { path = "../../meta", default-features = false, version = "0.1.0-beta", features = [
-	"ssr",
-] }
-leptos_router = { path = "../../router", default-features = false, version = "0.1.0-beta", features = [
-	"ssr",
-] }
-leptos_config = { path = "../../leptos_config", default-features = false, version = "0.1.0-beta" }
+leptos = { workspace = true, features = ["ssr"] }
+leptos_meta = { workspace = true, features = ["ssr"] }
+leptos_router = { workspace = true, features = ["ssr"] }
+leptos_config.workspace = true
 tokio = { version = "1.0", features = ["full"] }

integrations/axum/src/lib.rs

@@ -139,7 +139,7 @@ pub async fn handle_server_fns(
     req: Request<Body>,
 ) -> impl IntoResponse {
     // Axum Path extractor doesn't remove the first slash from the path, while Actix does
-    let fn_name: String = match fn_name.strip_prefix("/") {
+    let fn_name: String = match fn_name.strip_prefix('/') {
         Some(path) => path.to_string(),
         None => fn_name,
     };
@@ -180,15 +180,12 @@ pub async fn handle_server_fns(
                                     let res_options_outer = res_options.unwrap().0;
                                     let res_options_inner = res_options_outer.read().await;
                                     let (status, mut res_headers) = (
-                                        res_options_inner.status.clone(),
+                                        res_options_inner.status,
                                         res_options_inner.headers.clone(),
                                     );
 
-                                    match res.headers_mut() {
-                                        Some(header_ref) => {
-                                            header_ref.extend(res_headers.drain());
-                                        }
-                                        None => (),
+                                    if let Some(header_ref) = res.headers_mut() {
+                                           header_ref.extend(res_headers.drain());
                                     };
 
                                     if accept_header == Some("application/json")
@@ -237,9 +234,9 @@ pub async fn handle_server_fns(
                             Response::builder()
                                 .status(StatusCode::BAD_REQUEST)
                                 .body(Full::from(
-                                    format!("Could not find a server function at the route {:?}. \
+                                    format!("Could not find a server function at the route {fn_name}. \
                                     \n\nIt's likely that you need to call ServerFn::register() on the \
-                                    server function type, somewhere in your `main` function.", fn_name)
+                                    server function type, somewhere in your `main` function." )
                                 ))
                         }
                         .expect("could not build Response");
@@ -339,7 +336,7 @@ where
                 // the site was built with cargo run and not cargo-leptos
                 let bundle_path = match site_root.as_ref() {
                     "pkg" => "pkg".to_string(),
-                    _ => format!("{}/{}", site_root, pkg_path),
+                    _ => format!("{site_root}/{pkg_path}"),
                 };
 
                 let output_name = &options.output_name;
@@ -487,10 +484,9 @@ where
                     Box::pin(complete_stream) as PinnedHtmlStream
                 ));
 
-                match res_options.status {
-                    Some(status) => *res.status_mut() = status,
-                    None => (),
-                };
+                if let Some(status) = res_options.status {
+                    *res.status_mut() = status
+                }
                 let mut res_headers = res_options.headers.clone();
                 res.headers_mut().extend(res_headers.drain());
 

leptos/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -10,11 +10,11 @@ readme = "../README.md"
 
 [dependencies]
 cfg-if = "1"
-leptos_config = { path = "../leptos_config", default-features = false, version = "0.1.0-beta" }
-leptos_dom = { path = "../leptos_dom", default-features = false, version = "0.1.0-beta" }
-leptos_macro = { path = "../leptos_macro", default-features = false, version = "0.1.0-beta" }
-leptos_reactive = { path = "../leptos_reactive", default-features = false, version = "0.1.0-beta" }
-leptos_server = { path = "../leptos_server", default-features = false, version = "0.1.0-beta" }
+leptos_dom.workspace = true
+leptos_macro.workspace = true
+leptos_reactive.workspace = true
+leptos_server.workspace = true
+leptos_config.workspace = true
 tracing = "0.1"
 typed-builder = "0.11"
 

leptos/src/suspense.rs

@@ -1,10 +1,10 @@
 use cfg_if::cfg_if;
-use leptos_macro::component;
-use std::rc::Rc;
-use leptos_dom::{DynChild, Fragment, IntoView, Component};
-use leptos_reactive::{provide_context, Scope, SuspenseContext};
+use leptos_dom::{Component, DynChild, Fragment, IntoView};
 #[cfg(not(any(feature = "csr", feature = "hydrate")))]
 use leptos_dom::{HydrationCtx, HydrationKey};
+use leptos_macro::component;
+use leptos_reactive::{provide_context, Scope, SuspenseContext};
+use std::rc::Rc;
 
 /// If any [Resources](leptos_reactive::Resource) are read in the `children` of this
 /// component, it will show the `fallback` while they are loading. Once all are resolved,
@@ -88,8 +88,8 @@ where
                 } else {
                     // run the child; we'll probably throw this away, but it will register resource reads
                     let child = orig_child(cx).into_view(cx);
-            
-                    let initial = {    
+
+                    let initial = {
                         // no resources were read under this, so just return the child
                         if context.pending_resources.get() == 0 {
                             child.clone()
@@ -97,10 +97,10 @@ where
                         // show the fallback, but also prepare to stream HTML
                         else {
                             let orig_child = Rc::clone(&orig_child);
-                            
+
                             cx.register_suspense(
                                 context,
-                                &id_before_suspense.to_string(), 
+                                &id_before_suspense.to_string(),
                                 &current_id.to_string(),
                                 {
                                     let current_id = current_id.clone();
@@ -117,17 +117,17 @@ where
                                     }
                                 }
                             );
-                
+
                             // return the fallback for now, wrapped in fragment identifer
                             fallback().into_view(cx)
                         }
                     };
-            
+
                     HydrationCtx::continue_from(current_id.clone());
-            
+
                     initial
                 }
             }
         })
     })
-}
+}

leptos/src/transition.rs

@@ -1,6 +1,6 @@
 use leptos_dom::{Fragment, IntoView, View};
 use leptos_macro::component;
-use leptos_reactive::{ Scope, SignalSetter};
+use leptos_reactive::{Scope, SignalSetter};
 use std::{cell::RefCell, rc::Rc};
 
 /// If any [Resource](leptos_reactive::Resource)s are read in the `children` of this
@@ -66,7 +66,7 @@ pub fn Transition<F, E>(
     #[prop(optional)]
     set_pending: Option<SignalSetter<bool>>,
     /// Will be displayed once all resources have resolved.
-    children: Box<dyn Fn(Scope) -> Fragment>
+    children: Box<dyn Fn(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     F: Fn() -> E + 'static,
@@ -78,7 +78,6 @@ where
         crate::SuspenseProps::builder()
             .fallback({
                 let prev_child = Rc::clone(&prev_children);
-                let set_pending = set_pending.clone();
                 move || {
                     if let Some(set_pending) = &set_pending {
                         set_pending.set(true);
@@ -98,6 +97,6 @@ where
                 }
                 frag
             }))
-            .build()
+            .build(),
     )
-}
+}

leptos_config/src/lib.rs

@@ -119,8 +119,7 @@ impl TryFrom<String> for Env {
             "prod" => Ok(Self::PROD),
             "production" => Ok(Self::PROD),
             other => Err(format!(
-                "{} is not a supported environment. Use either `dev` or `production`.",
-                other
+                "{other} is not a supported environment. Use either `dev` or `production`."
             )),
         }
     }

leptos_dom/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos_dom"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -12,12 +12,12 @@ cfg-if = "1"
 drain_filter_polyfill = "0.1"
 educe = "0.4"
 futures = "0.3"
-gloo = "0.8"
+gloo = { version = "0.8", features = ["futures"] }
 html-escape = "0.2"
 indexmap = "1.9"
 itertools = "0.10"
 js-sys = "0.3"
-leptos_reactive = { path = "../leptos_reactive", default-features = false, version = "0.1.0-beta" }
+leptos_reactive.workspace = true
 once_cell = "1"
 pad-adapter = "0.1"
 paste = "1"
@@ -140,6 +140,7 @@ features = [
 ]
 
 [features]
+default = []
 web = ["leptos_reactive/csr"]
 ssr = ["leptos_reactive/ssr"]
 stable = ["leptos_reactive/stable"]

leptos_dom/examples/test-bench/Cargo.toml

@@ -6,8 +6,10 @@ edition = "2021"
 [dependencies]
 console_error_panic_hook = "0.1"
 gloo = { version = "0.8", features = ["futures"] }
-leptos = { path = "../../../leptos" }
+leptos = { path = "../../../leptos", features = ["tracing"] }
 tracing = "0.1"
 tracing-subscriber = "0.3"
 wasm-bindgen-futures = "0.4"
-web-sys = "0.3"
+web-sys = "0.3"
+
+[workspace]

leptos_dom/examples/test-bench/src/main.rs

@@ -6,6 +6,7 @@ extern crate tracing;
 mod utils;
 
 use leptos::*;
+use tracing::field::debug;
 use tracing_subscriber::util::SubscriberInitExt;
 
 fn main() {
@@ -42,6 +43,7 @@ fn view_fn(cx: Scope) -> impl IntoView {
   let (is_a, set_is_a) = create_signal(cx, true);
 
   let handle_toggle = move |_| {
+      trace!("toggling");
     if is_a() {
       set_b(a());
 
@@ -58,6 +60,7 @@ fn view_fn(cx: Scope) -> impl IntoView {
       <div>
         <button on:click=handle_toggle>"Toggle"</button>
       </div>
+      <Example/>
       <A child=Signal::from(a) />
       <A child=Signal::from(b) />
     </>
@@ -71,7 +74,26 @@ fn A(cx: Scope, child: Signal<View>) -> impl IntoView {
 
 #[component]
 fn Example(cx: Scope) -> impl IntoView {
-  view! { cx,
+    trace!("rendering <Example/>");
+    
+    let (value, set_value) = create_signal(cx, 10);
+
+    let memo = create_memo(cx, move |_| value() * 2);
+    let derived = Signal::derive(cx, move || {
+        value() * 3
+    });
+
+    create_effect(cx, move |_| {
+        trace!("logging value of derived..., {}", derived.get());
+    });
+
+
+    set_timeout(move || { set_value.update(|v| *v += 1)}, std::time::Duration::from_millis(50));
+
+    view! { cx,
     <h1>"Example"</h1>
+    <button on:click=move |_| set_value.update(|value| *value += 1)>
+      "Click me"
+    </button>
   }
 }

leptos_dom/src/components/dyn_child.rs

@@ -154,10 +154,7 @@ where
     let component = DynChildRepr::new();
 
     #[cfg(all(target_arch = "wasm32", feature = "web"))]
-    let (frag, closing) = (
-      component.document_fragment.clone(),
-      component.closing.node.clone(),
-    );
+    let closing = component.closing.node.clone();
 
     let child = component.child.clone();
 
@@ -189,7 +186,9 @@ where
           // or to reuse it in the case of a text node
 
           // TODO check does this still detect moves correctly?
-          let was_child_moved = prev_t.is_none() && child.get_closing_node().next_sibling().as_ref() != Some(&closing);
+          let was_child_moved = prev_t.is_none()
+            && child.get_closing_node().next_sibling().as_ref()
+              != Some(&closing);
 
           // If the previous child was a text node, we would like to
           // make use of it again if our current child is also a text

leptos_dom/src/components/each.rs

@@ -41,7 +41,7 @@ cfg_if! {
 use smallvec::SmallVec;
 use std::{borrow::Cow, cell::RefCell, fmt, hash::Hash, ops::Deref, rc::Rc};
 
-/// The internal representation of the [`EachKey`] core-component.
+/// The internal representation of the [`Each`] core-component.
 #[derive(Clone, PartialEq, Eq)]
 pub struct EachRepr {
   #[cfg(all(target_arch = "wasm32", feature = "web"))]
@@ -156,7 +156,7 @@ impl Mountable for EachRepr {
   }
 }
 
-/// The internal representation of an [`EachKey`] item.
+/// The internal representation of an [`Each`] item.
 #[derive(PartialEq, Eq)]
 pub(crate) struct EachItem {
   #[cfg(all(target_arch = "wasm32", feature = "web"))]
@@ -293,7 +293,7 @@ where
   K: Eq + Hash + 'static,
   T: 'static,
 {
-  /// Creates a new [`EachKey`] component.
+  /// Creates a new [`Each`] component.
   pub fn new(items_fn: IF, key_fn: KF, each_fn: EF) -> Self {
     Self {
       items_fn,

leptos_dom/src/events.rs

@@ -16,10 +16,20 @@ thread_local! {
 pub fn add_event_listener<E>(
   target: &web_sys::Element,
   event_name: Cow<'static, str>,
-  cb: impl FnMut(E) + 'static,
+  mut cb: impl FnMut(E) + 'static,
 ) where
   E: FromWasmAbi + 'static,
 {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move |e| {
+        let _guard = span.enter();
+        cb(e);
+      };
+    }
+  }
+
   let cb = Closure::wrap(Box::new(cb) as Box<dyn FnMut(E)>).into_js_value();
   let key = event_delegation_key(&event_name);
   _ = js_sys::Reflect::set(target, &JsValue::from_str(&key), &cb);
@@ -31,10 +41,20 @@ pub fn add_event_listener<E>(
 pub fn add_event_listener_undelegated<E>(
   target: &web_sys::Element,
   event_name: &str,
-  cb: impl FnMut(E) + 'static,
+  mut cb: impl FnMut(E) + 'static,
 ) where
   E: FromWasmAbi + 'static,
 {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move |e| {
+        let _guard = span.enter();
+        cb(e);
+      };
+    }
+  }
+
   let event_name = intern(event_name);
   let cb = Closure::wrap(Box::new(cb) as Box<dyn FnMut(E)>).into_js_value();
   _ = target.add_event_listener_with_callback(event_name, cb.unchecked_ref());
@@ -97,7 +117,20 @@ pub(crate) fn add_delegated_event_listener(event_name: Cow<'static, str>) {
         }
       };
 
-      crate::window_event_listener(&event_name, handler);
+      cfg_if::cfg_if! {
+        if #[cfg(debug_assertions)] {
+          let span = ::tracing::Span::current();
+          let handler = move |e| {
+            let _guard = span.enter();
+            handler(e);
+          };
+        }
+      }
+
+      let handler = Box::new(handler) as Box<dyn FnMut(web_sys::Event)>;
+      let handler = Closure::wrap(handler).into_js_value();
+      _ = crate::window()
+        .add_event_listener_with_callback(&event_name, handler.unchecked_ref());
 
       // register that we've created handler
       events.insert(event_name);

leptos_dom/src/helpers.rs

@@ -71,21 +71,57 @@ pub fn event_target_checked(ev: &web_sys::Event) -> bool {
 
 /// Runs the given function between the next repaint
 /// using [`Window.requestAnimationFrame`](https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame).
-pub fn request_animation_frame(cb: impl FnMut() + 'static) {
-  let cb = Closure::wrap(Box::new(cb) as Box<dyn FnMut()>).into_js_value();
+#[cfg_attr(debug_assertions, instrument(level = "trace", skip_all))]
+pub fn request_animation_frame(cb: impl FnOnce() + 'static) {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move || {
+        let _guard = span.enter();
+        cb();
+      };
+    }
+  }
+
+  let cb = Closure::once_into_js(cb);
   _ = window().request_animation_frame(cb.as_ref().unchecked_ref());
 }
 
 /// Queues the given function during an idle period  
 /// using [`Window.requestIdleCallback`](https://developer.mozilla.org/en-US/docs/Web/API/window/requestIdleCallback).
+#[cfg_attr(debug_assertions, instrument(level = "trace", skip_all))]
 pub fn request_idle_callback(cb: impl Fn() + 'static) {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move || {
+        let _guard = span.enter();
+        cb();
+      };
+    }
+  }
+
   let cb = Closure::wrap(Box::new(cb) as Box<dyn Fn()>).into_js_value();
   _ = window().request_idle_callback(cb.as_ref().unchecked_ref());
 }
 
 /// Executes the given function after the given duration of time has passed.
 /// [`setTimeout()`](https://developer.mozilla.org/en-US/docs/Web/API/setTimeout).
+#[cfg_attr(
+  debug_assertions,
+  instrument(level = "trace", skip_all, fields(duration = ?duration))
+)]
 pub fn set_timeout(cb: impl FnOnce() + 'static, duration: Duration) {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move || {
+        let _guard = span.enter();
+        cb();
+      };
+    }
+  }
+
   let cb = Closure::once_into_js(Box::new(cb) as Box<dyn FnOnce()>);
   _ = window().set_timeout_with_callback_and_timeout_and_arguments_0(
     cb.as_ref().unchecked_ref(),
@@ -107,10 +143,24 @@ impl IntervalHandle {
 
 /// Repeatedly calls the given function, with a delay of the given duration between calls.
 /// See [`setInterval()`](https://developer.mozilla.org/en-US/docs/Web/API/setInterval).
+#[cfg_attr(
+  debug_assertions,
+  instrument(level = "trace", skip_all, fields(duration = ?duration))
+)]
 pub fn set_interval(
   cb: impl Fn() + 'static,
   duration: Duration,
 ) -> Result<IntervalHandle, JsValue> {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move || {
+        let _guard = span.enter();
+        cb();
+      };
+    }
+  }
+
   let cb = Closure::wrap(Box::new(cb) as Box<dyn Fn()>).into_js_value();
   let handle = window()
     .set_interval_with_callback_and_timeout_and_arguments_0(
@@ -121,10 +171,24 @@ pub fn set_interval(
 }
 
 /// Adds an event listener to the `Window`.
+#[cfg_attr(
+  debug_assertions,
+  instrument(level = "trace", skip_all, fields(event_name = %event_name))
+)]
 pub fn window_event_listener(
   event_name: &str,
   cb: impl Fn(web_sys::Event) + 'static,
 ) {
+  cfg_if::cfg_if! {
+    if #[cfg(debug_assertions)] {
+      let span = ::tracing::Span::current();
+      let cb = move |e| {
+        let _guard = span.enter();
+        cb(e);
+      };
+    }
+  }
+
   if !is_server() {
     let handler = Box::new(cb) as Box<dyn FnMut(web_sys::Event)>;
 

leptos_dom/src/html.rs

@@ -90,7 +90,12 @@ where
         element: el,
       };
 
-      HtmlElement { cx, element }
+      HtmlElement { 
+          cx, 
+          element,
+          #[cfg(debug_assertions)]
+          span: ::tracing::Span::current()
+      }
     }
 
     #[cfg(not(all(target_arch = "wasm32", feature = "web")))]
@@ -192,6 +197,8 @@ cfg_if! {
     /// Represents an HTML element.
     #[derive(Clone)]
     pub struct HtmlElement<El: ElementDescriptor> {
+      #[cfg(debug_assertions)]
+      pub(crate) span: ::tracing::Span,
       pub(crate) cx: Scope,
       pub(crate) element: El,
     }
@@ -229,13 +236,15 @@ where
   }
 }
 
-impl<El: ElementDescriptor> HtmlElement<El> {
+impl<El: ElementDescriptor + 'static> HtmlElement<El> {
   fn new(cx: Scope, element: El) -> Self {
     cfg_if! {
       if #[cfg(all(target_arch = "wasm32", feature = "web"))] {
         Self {
           cx,
           element,
+          #[cfg(debug_assertions)]
+          span: ::tracing::Span::current()
         }
       } else {
         Self {
@@ -272,6 +281,8 @@ impl<El: ElementDescriptor> HtmlElement<El> {
         let Self {
           cx,
           element,
+          #[cfg(debug_assertions)]
+          span        
         } = self;
 
         HtmlElement {
@@ -281,6 +292,8 @@ impl<El: ElementDescriptor> HtmlElement<El> {
             element: element.as_ref().clone(),
             is_void: element.is_void(),
           },
+          #[cfg(debug_assertions)]
+          span
         }
       } else {
         let Self {
@@ -346,6 +359,71 @@ impl<El: ElementDescriptor> HtmlElement<El> {
     self
   }
 
+  /// Runs the callback when this element has been mounted to the DOM.
+  ///
+  /// ### Important Note
+  /// This method will only ever run at most once. If this element
+  /// is unmounted and remounted, or moved somewhere else, it will not
+  /// re-run unless you call this method again.
+  pub fn on_mount(self, f: impl FnOnce(Self) + 'static) -> Self {
+    #[cfg(all(target_arch = "wasm32", feature = "web"))]
+    {
+      use futures::future::poll_fn;
+      use once_cell::unsync::OnceCell;
+      use std::{
+        cell::RefCell,
+        rc::Rc,
+        task::{Poll, Waker},
+      };
+
+      let this = self.clone();
+      let el = self.element.as_ref().clone();
+
+      wasm_bindgen_futures::spawn_local(async move {
+        while !crate::document().body().unwrap().contains(Some(&el)) {
+          // We need to cook ourselves a small future that resolves
+          // when the next animation frame is available
+          let waker = Rc::new(RefCell::new(None::<Waker>));
+          let ready = Rc::new(OnceCell::new());
+
+          crate::request_animation_frame({
+            let waker = waker.clone();
+            let ready = ready.clone();
+
+            move || {
+              let _ = ready.set(());
+              if let Some(waker) = &*waker.borrow() {
+                waker.wake_by_ref();
+              }
+            }
+          });
+
+          // Wait for the animation frame to become available
+          poll_fn(move |cx| {
+            let mut waker_borrow = waker.borrow_mut();
+
+            *waker_borrow = Some(cx.waker().clone());
+
+            if ready.get().is_some() {
+              Poll::Ready(())
+            } else {
+              Poll::<()>::Pending
+            }
+          })
+          .await;
+        }
+
+        f(this);
+      });
+    }
+
+    #[cfg(not(all(target_arch = "wasm32", feature = "web")))]
+    {
+      let _ = f;
+    }
+    self
+  }
+
   /// Adds an attribute to this element.
   #[track_caller]
   pub fn attr(
@@ -506,10 +584,22 @@ impl<El: ElementDescriptor> HtmlElement<El> {
   pub fn on<E: EventDescriptor + 'static>(
     self,
     event: E,
-    event_handler: impl FnMut(E::EventType) + 'static,
+    #[allow(unused_mut)] // used for tracing in debug
+    mut event_handler: impl FnMut(E::EventType) + 'static,
   ) -> Self {
     #[cfg(all(target_arch = "wasm32", feature = "web"))]
     {
+        cfg_if! {
+            if #[cfg(debug_assertions)] {
+                let onspan = ::tracing::span!(
+                    parent: &self.span,
+                    ::tracing::Level::TRACE,
+                    "on",
+                    event = %event.name()
+                );
+                let _onguard = onspan.enter();
+            }
+        }
       let event_name = event.name();
 
       if event.bubbles() {
@@ -618,9 +708,9 @@ impl<El: ElementDescriptor> IntoView for HtmlElement<El> {
       let children = children;
 
       if attrs.iter_mut().any(|(name, _)| name == "id") {
-        attrs.push(("leptos-hk".into(), format!("_{}", id).into()));
+        attrs.push(("leptos-hk".into(), format!("_{id}").into()));
       } else {
-        attrs.push(("id".into(), format!("_{}", id).into()));
+        attrs.push(("id".into(), format!("_{id}").into()));
       }
 
       element.attrs = attrs;
@@ -800,6 +890,17 @@ macro_rules! generate_html_tags {
         }
 
         #[$meta]
+      #[cfg_attr(
+        debug_assertions,
+        instrument(
+          level = "trace",
+          name = "HtmlElement",
+          skip_all,
+          fields(
+            tag = %format!("<{}/>", stringify!($tag))
+          )
+        )
+      )]
         pub fn $tag(cx: Scope) -> HtmlElement<[<$tag:camel $($trailing_)?>]> {
           HtmlElement::new(cx, [<$tag:camel $($trailing_)?>]::default())
         }

leptos_dom/src/hydration.rs

@@ -3,9 +3,9 @@ use std::{cell::RefCell, fmt::Display};
 #[cfg(all(target_arch = "wasm32", feature = "web"))]
 use once_cell::unsync::Lazy as LazyCell;
 
-/// We can tell if we start in hydration mode by checking to see if the
-/// id "_0" is present in the DOM. If it is, we know we are hydrating from
-/// the server, if not, we are starting off in CSR
+// We can tell if we start in hydration mode by checking to see if the
+// id "_0-0-0" is present in the DOM. If it is, we know we are hydrating from
+// the server, if not, we are starting off in CSR
 #[cfg(all(target_arch = "wasm32", feature = "web"))]
 thread_local! {
   static IS_HYDRATING: RefCell<LazyCell<bool>> = RefCell::new(LazyCell::new(|| {

leptos_dom/src/lib.rs

@@ -192,7 +192,7 @@ cfg_if! {
 }
 
 impl Element {
-  /// Converts this leptos [`Element`] into [`HtmlElement<AnyElement`].
+  /// Converts this leptos [`Element`] into [`HtmlElement<AnyElement>`].
   pub fn into_html_element(self, cx: Scope) -> HtmlElement<AnyElement> {
     #[cfg(all(target_arch = "wasm32", feature = "web"))]
     {
@@ -206,7 +206,12 @@ impl Element {
         is_void: false,
       };
 
-      HtmlElement { cx, element }
+      HtmlElement {
+          cx,
+          element,
+          #[cfg(debug_assertions)]
+          span: ::tracing::Span::current()
+      }
     }
 
     #[cfg(not(all(target_arch = "wasm32", feature = "web")))]
@@ -327,7 +332,8 @@ pub struct Text {
   /// to possibly reuse a previous node.
   #[cfg(all(target_arch = "wasm32", feature = "web"))]
   node: web_sys::Node,
-  content: Cow<'static, str>,
+  /// The current contents of the text node.
+  pub content: Cow<'static, str>,
 }
 
 impl fmt::Debug for Text {
@@ -541,8 +547,19 @@ impl View {
   pub fn on<E: ev::EventDescriptor + 'static>(
     self,
     event: E,
-    event_handler: impl FnMut(E::EventType) + 'static,
+    mut event_handler: impl FnMut(E::EventType) + 'static,
   ) -> Self {
+    cfg_if::cfg_if! {
+      if #[cfg(debug_assertions)] {
+        trace!("calling on() {}", event.name());
+        let span = ::tracing::Span::current();
+        let event_handler = move |e| {
+          let _guard = span.enter();
+          event_handler(e);
+        };
+      }
+    }
+
     self.on_impl(event, Box::new(event_handler))
   }
 

leptos_dom/src/logging.rs

@@ -45,7 +45,7 @@ macro_rules! debug_warn {
 /// or via `println!()` (if not in the browser).
 pub fn console_log(s: &str) {
   if is_server() {
-    println!("{}", s);
+    println!("{s}");
   } else {
     web_sys::console::log_1(&JsValue::from_str(s));
   }
@@ -55,7 +55,7 @@ pub fn console_log(s: &str) {
 /// or via `println!()` (if not in the browser).
 pub fn console_warn(s: &str) {
   if is_server() {
-    eprintln!("{}", s);
+    eprintln!("{s}");
   } else {
     web_sys::console::warn_1(&JsValue::from_str(s));
   }
@@ -65,7 +65,7 @@ pub fn console_warn(s: &str) {
 /// or via `println!()` (if not in the browser).
 pub fn console_error(s: &str) {
   if is_server() {
-    eprintln!("{}", s);
+    eprintln!("{s}");
   } else {
     web_sys::console::warn_1(&JsValue::from_str(s));
   }
@@ -77,7 +77,7 @@ pub fn console_debug_warn(s: &str) {
   cfg_if! {
       if #[cfg(debug_assertions)] {
           if is_server() {
-              eprintln!("{}", s);
+              eprintln!("{s}");
           } else {
               web_sys::console::warn_1(&JsValue::from_str(s));
           }

leptos_macro/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos_macro"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -22,15 +22,15 @@ quote = "1"
 syn = { version = "1", features = ["full"] }
 syn-rsx = "0.9"
 uuid = { version = "1", features = ["v4"] }
-leptos_dom = { path = "../leptos_dom", version = "0.1.0-beta" }
-leptos_reactive = { path = "../leptos_reactive", version = "0.1.0-beta" }
-leptos_server = { path = "../leptos_server", version = "0.1.0-beta" }
+leptos_dom.workspace = true
+leptos_reactive.workspace = true
+leptos_server.workspace = true
 lazy_static = "1.4"
 
 [dev-dependencies]
 log = "0.4"
 typed-builder = "0.10"
-leptos = { path = "../leptos" }
+leptos.workspace = true
 
 [features]
 default = ["ssr"]

leptos_macro/src/lib.rs

@@ -176,6 +176,25 @@ mod server;
 /// # });
 /// ```
 ///
+/// However, you can pass arbitrary class names using the syntax `class=("name", value)`.
+/// ```rust
+/// # use leptos::*;
+/// # run_scope(create_runtime(), |cx| {
+/// # if !cfg!(any(feature = "csr", feature = "hydrate")) {
+/// let (count, set_count) = create_signal(cx, 2);
+/// // this allows you to use CSS frameworks that include complex class names
+/// view! { cx,
+///   <div 
+///     class=("is-[this_-_really]-necessary-42", move || count() < 3)
+///   >
+///     "Now you see me, now you don’t."
+///   </div>
+/// }
+/// # ;
+/// # }
+/// # });
+/// ```
+///
 /// 8. You can use the `_ref` attribute to store a reference to its DOM element in a
 ///    [NodeRef](leptos_reactive::NodeRef) to use later.
 /// ```rust
@@ -358,12 +377,12 @@ pub fn view(tokens: TokenStream) -> TokenStream {
 /// ```
 ///
 /// 5. You can access the children passed into the component with the `children` property, which takes
-///    an argument of the form `Box<dyn Fn(Scope) -> Fragment>`.
+///    an argument of the form `Box<dyn FnOnce(Scope) -> Fragment>`.
 ///
 /// ```
 /// # use leptos::*;
 /// #[component]
-/// fn ComponentWithChildren(cx: Scope, children: Box<dyn Fn(Scope) -> Fragment>) -> impl IntoView {
+/// fn ComponentWithChildren(cx: Scope, children: Box<dyn FnOnce(Scope) -> Fragment>) -> impl IntoView {
 ///   view! {
 ///     cx,
 ///     <ul>

leptos_macro/src/props.rs

@@ -105,11 +105,11 @@ mod struct_info {
                 builder_attr,
                 builder_name: syn::Ident::new(&builder_name, proc_macro2::Span::call_site()),
                 conversion_helper_trait_name: syn::Ident::new(
-                    &format!("{}_Optional", builder_name),
+                    &format!("{builder_name}_Optional"),
                     proc_macro2::Span::call_site(),
                 ),
                 core: syn::Ident::new(
-                    &format!("{}_core", builder_name),
+                    &format!("{builder_name}_core"),
                     proc_macro2::Span::call_site(),
                 ),
             })
@@ -282,7 +282,7 @@ mod struct_info {
             });
             let reconstructing = self.included_fields().map(|f| f.name);
 
-            let &FieldInfo {
+            let FieldInfo {
                 name: ref field_name,
                 ty: ref field_type,
                 ..
@@ -391,7 +391,7 @@ mod struct_info {
                 ),
                 proc_macro2::Span::call_site(),
             );
-            let repeated_fields_error_message = format!("Repeated field {}", field_name);
+            let repeated_fields_error_message = format!("Repeated field {field_name}");
 
             Ok(quote! {
                 #[allow(dead_code, non_camel_case_types, missing_docs)]
@@ -513,7 +513,7 @@ mod struct_info {
                 ),
                 proc_macro2::Span::call_site(),
             );
-            let early_build_error_message = format!("Missing required field {}", field_name);
+            let early_build_error_message = format!("Missing required field {field_name}");
 
             Ok(quote! {
                 #[doc(hidden)]
@@ -622,7 +622,7 @@ mod struct_info {
                         // I'd prefer “a” or “an” to “its”, but determining which is grammatically
                         // correct is roughly impossible.
                         let doc =
-                            format!("Finalise the builder and create its [`{}`] instance", name);
+                            format!("Finalise the builder and create its [`{name}`] instance");
                         quote!(#[doc = #doc])
                     }
                 }
@@ -718,7 +718,7 @@ mod struct_info {
                         }
                         _ => Err(Error::new_spanned(
                             &assign,
-                            format!("Unknown parameter {:?}", name),
+                            format!("Unknown parameter {name:?}"),
                         )),
                     }
                 }
@@ -732,7 +732,7 @@ mod struct_info {
                         }
                         _ => Err(Error::new_spanned(
                             &path,
-                            format!("Unknown parameter {:?}", name),
+                            format!("Unknown parameter {name:?}"),
                         )),
                     }
                 }
@@ -747,7 +747,7 @@ mod struct_info {
                         let call_func = quote!(#call_func);
                         Error::new_spanned(
                             &call.func,
-                            format!("Illegal builder setting group {}", call_func),
+                            format!("Illegal builder setting group {call_func}"),
                         )
                     })?;
                     match subsetting_name.as_str() {
@@ -759,7 +759,7 @@ mod struct_info {
                         }
                         _ => Err(Error::new_spanned(
                             &call.func,
-                            format!("Illegal builder setting group name {}", subsetting_name),
+                            format!("Illegal builder setting group name {subsetting_name}"),
                         )),
                     }
                 }
@@ -924,7 +924,7 @@ mod field_info {
                                 let tokenized_code = TokenStream::from_str(&code.value())?;
                                 self.default = Some(
                                     syn::parse(tokenized_code.into())
-                                        .map_err(|e| Error::new_spanned(code, format!("{}", e)))?,
+                                        .map_err(|e| Error::new_spanned(code, format!("{e}")))?,
                                 );
                             } else {
                                 return Err(Error::new_spanned(assign.right, "Expected string"));
@@ -933,7 +933,7 @@ mod field_info {
                         }
                         _ => Err(Error::new_spanned(
                             &assign,
-                            format!("Unknown parameter {:?}", name),
+                            format!("Unknown parameter {name:?}"),
                         )),
                     }
                 }
@@ -950,7 +950,7 @@ mod field_info {
                         }
                         _ => Err(Error::new_spanned(
                             &path,
-                            format!("Unknown parameter {:?}", name),
+                            format!("Unknown parameter {name:?}"),
                         )),
                     }
                 }
@@ -965,7 +965,7 @@ mod field_info {
                         let call_func = quote!(#call_func);
                         Error::new_spanned(
                             &call.func,
-                            format!("Illegal builder setting group {}", call_func),
+                            format!("Illegal builder setting group {call_func}"),
                         )
                     })?;
                     match subsetting_name.as_ref() {
@@ -977,7 +977,7 @@ mod field_info {
                         }
                         _ => Err(Error::new_spanned(
                             &call.func,
-                            format!("Illegal builder setting group name {}", subsetting_name),
+                            format!("Illegal builder setting group name {subsetting_name}"),
                         )),
                     }
                 }
@@ -1047,7 +1047,7 @@ mod field_info {
                         }
                         _ => Err(Error::new_spanned(
                             &assign,
-                            format!("Unknown parameter {:?}", name),
+                            format!("Unknown parameter {name:?}"),
                         )),
                     }
                 }

leptos_macro/src/server.rs

@@ -47,7 +47,7 @@ pub fn server_macro_impl(args: proc_macro::TokenStream, s: TokenStream2) -> Resu
             use proc_macro::Span;
             let span = Span::call_site();
             #[cfg(not(target_os = "windows"))]
-            let url = format!("{}/{}", span.source_file().path().to_string_lossy(), fn_name_as_str).replace("/", "-");
+            let url = format!("{}/{}", span.source_file().path().to_string_lossy(), fn_name_as_str).replace('/', "-");
             #[cfg(target_os = "windows")]
             let url = format!("{}/{}", span.source_file().path().to_string_lossy(), fn_name_as_str).replace("\\", "-");
         } else {

leptos_macro/src/view.rs

@@ -1,6 +1,6 @@
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::{format_ident, quote, quote_spanned};
-use syn::{spanned::Spanned, ExprPath};
+use syn::{spanned::Spanned, ExprPath, Expr, ExprLit, Lit};
 use syn_rsx::{Node, NodeAttribute, NodeElement, NodeName};
 
 use crate::{is_component_node, Mode};
@@ -412,7 +412,11 @@ fn set_class_attribute_ssr(
                     if a.value.as_ref().and_then(value_to_string).is_some() {
                         None
                     } else {
-                        Some((a.key.span(), &a.value))
+                        if fancy_class_name(&a.key.to_string(), cx, a).is_some() {
+                            None
+                        } else {
+                            Some((a.key.span(), &a.value))
+                        }
                     }
                 } else {
                     None
@@ -429,6 +433,14 @@ fn set_class_attribute_ssr(
         .filter_map(|node| {
             if let Node::Attribute(node) = node {
                 let name = node.key.to_string();
+                if name == "class" {
+                    return if let Some((_, name, value)) = fancy_class_name(&name, &cx, &node) {
+                       let span = node.key.span();
+                       Some((span, name, value))
+                    } else {
+                       None
+                    }
+                }
                 if name.starts_with("class:") || name.starts_with("class-") {
                     let name = if name.starts_with("class:") {
                         name.replacen("class:", "", 1)
@@ -752,6 +764,12 @@ fn attribute_to_tokens(cx: &Ident, node: &NodeAttribute) -> TokenStream {
         }
     } else {
         let name = name.replacen("attr:", "", 1);
+        
+        if let Some((fancy, _, _)) = fancy_class_name(&name, &cx, &node) {
+            return fancy;
+        }
+
+        // all other attributes
         let value = match node.value.as_ref() {
             Some(value) => {
                 let value = value.as_ref();
@@ -866,7 +884,11 @@ fn ident_from_tag_name(tag_name: &NodeName) -> Ident {
             .last()
             .map(|segment| segment.ident.clone())
             .expect("element needs to have a name"),
-        NodeName::Block(_) => panic!("blocks not allowed in tag-name position"),
+        NodeName::Block(_) => {
+            let span = tag_name.span();
+            proc_macro_error::emit_error!(span, "blocks not allowed in tag-name position");
+            Ident::new("", span)
+        }
         _ => Ident::new(
             &tag_name.to_string().replace(['-', ':'], "_"),
             tag_name.span(),
@@ -1044,3 +1066,44 @@ fn parse_event(event_name: &str) -> (&str, bool) {
         (event_name, false)
     }
 }
+
+fn fancy_class_name<'a>(name: &str, cx: &Ident, node: &'a NodeAttribute) -> Option<(TokenStream, String, &'a Expr)> {
+    // special case for complex class names: 
+    // e.g., Tailwind `class=("mt-[calc(100vh_-_3rem)]", true)`
+    if name == "class" {
+        if let Some(expr) = node.value.as_ref() {
+            if let syn::Expr::Tuple(tuple) = expr.as_ref() {
+                if tuple.elems.len() == 2 {
+                    let span = node.key.span();
+                    let class = quote_spanned! {
+                        span => .class
+                    };
+                    let class_name = &tuple.elems[0];
+                    let class_name = if let Expr::Lit(ExprLit { lit: Lit::Str(s), .. }) = class_name {
+                        s.value()
+                    } else {
+                        proc_macro_error::emit_error!(
+                            class_name.span(),
+                            "class name must be a string literal"
+                        );
+                        Default::default()
+                    };
+                    let value = &tuple.elems[1];
+                    return Some((
+                        quote! {
+                            #class(#class_name, (#cx, #value))
+                        },
+                        class_name,
+                        value
+                    ))
+                } else {
+                    proc_macro_error::emit_error!(
+                        tuple.span(),
+                        "class tuples must have two elements."
+                    )
+                }
+            }
+        }
+    }
+    None
+}

leptos_reactive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos_reactive"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -20,6 +20,7 @@ serde_json = "1"
 base64 = "0.13"
 thiserror = "1"
 tokio = { version = "1", features = ["rt"], optional = true }
+tracing = "0.1"
 wasm-bindgen = "0.2"
 wasm-bindgen-futures = "0.4"
 web-sys = { version = "0.3", features = [
@@ -47,4 +48,29 @@ miniserde = ["dep:miniserde"]
 
 [package.metadata.cargo-all-features]
 denylist = ["stable"]
-
+skip_feature_sets = [
+  [
+    "csr",
+    "ssr",
+  ],
+  [
+    "csr",
+    "hydrate",
+  ],
+  [
+    "ssr",
+    "hydrate",
+  ],
+  [
+    "serde",
+    "serde-lite",
+  ],
+  [
+    "serde-lite",
+    "miniserde",
+  ],
+  [
+    "serde",
+    "miniserde",
+  ],
+]

leptos_reactive/src/effect.rs

@@ -47,13 +47,26 @@ use std::fmt::Debug;
 /// # }
 /// # }).dispose();
 /// ```
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+            ty = %std::any::type_name::<T>()
+        )
+    )
+)]
+#[track_caller]
 pub fn create_effect<T>(cx: Scope, f: impl Fn(Option<T>) -> T + 'static)
 where
     T: 'static,
 {
     cfg_if! {
         if #[cfg(not(feature = "ssr"))] {
-            create_isomorphic_effect(cx, f);
+            let e = cx.runtime.create_effect(f);
+            cx.with_scope_property(|prop| prop.push(ScopeProperty::Effect(e)))
         } else {
             // clear warnings
             _ = cx;
@@ -88,6 +101,18 @@ where
 /// });
 /// # assert_eq!(b(), 2);
 /// # }).dispose();
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+            ty = %std::any::type_name::<T>()
+        )
+    )
+)]
+#[track_caller]
 pub fn create_isomorphic_effect<T>(cx: Scope, f: impl Fn(Option<T>) -> T + 'static)
 where
     T: 'static,
@@ -97,6 +122,17 @@ where
 }
 
 #[doc(hidden)]
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+            ty = %std::any::type_name::<T>()
+        )
+    )
+)]
 pub fn create_render_effect<T>(cx: Scope, f: impl Fn(Option<T>) -> T + 'static)
 where
     T: 'static,
@@ -116,6 +152,8 @@ where
 {
     pub(crate) f: F,
     pub(crate) value: RefCell<Option<T>>,
+    #[cfg(debug_assertions)]
+    pub(crate) defined_at: &'static std::panic::Location<'static>,
 }
 
 pub(crate) trait AnyEffect {
@@ -127,6 +165,19 @@ where
     T: 'static,
     F: Fn(Option<T>) -> T,
 {
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            name = "Effect::run()",
+            level = "debug",
+            skip_all,
+            fields(
+              id = ?id,
+              defined_at = %self.defined_at,
+              ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn run(&self, id: EffectId, runtime: RuntimeId) {
         with_runtime(runtime, |runtime| {
             // clear previous dependencies
@@ -162,6 +213,17 @@ impl EffectId {
         })
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            name = "Effect::cleanup()",
+            level = "debug",
+            skip_all,
+            fields(
+              id = ?self,
+            )
+        )
+    )]
     pub(crate) fn cleanup(&self, runtime: &Runtime) {
         let sources = runtime.effect_sources.borrow();
         if let Some(sources) = sources.get(*self) {

leptos_reactive/src/lib.rs

@@ -66,11 +66,13 @@
 //! });
 //! ```
 
+#[cfg_attr(debug_assertions, macro_use)]
+pub extern crate tracing;
+
 mod context;
 mod effect;
 mod hydration;
 mod memo;
-
 mod resource;
 mod runtime;
 mod scope;

leptos_reactive/src/memo.rs

@@ -54,6 +54,16 @@ use std::fmt::Debug;
 /// });
 /// # }).dispose();
 /// ```
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            cx = ?cx.id,
+        )
+    )
+)]
 pub fn create_memo<T>(cx: Scope, f: impl Fn(Option<&T>) -> T + 'static) -> Memo<T>
 where
     T: PartialEq + Debug + 'static,
@@ -115,7 +125,10 @@ where
 /// # }).dispose();
 /// ```
 #[derive(Debug, PartialEq, Eq)]
-pub struct Memo<T>(pub(crate) ReadSignal<Option<T>>)
+pub struct Memo<T>(
+    pub(crate) ReadSignal<Option<T>>,
+    #[cfg(debug_assertions)] pub(crate) &'static std::panic::Location<'static>,
+)
 where
     T: 'static;
 
@@ -124,13 +137,30 @@ where
     T: 'static,
 {
     fn clone(&self) -> Self {
-        Self(self.0)
+        Self(
+            self.0,
+            #[cfg(debug_assertions)]
+            self.1,
+        )
     }
 }
 
 impl<T> Copy for Memo<T> {}
 
 impl<T> UntrackedGettableSignal<T> for Memo<T> {
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "Memo::get_untracked()",
+            skip_all,
+            fields(
+                id = ?self.0.id,
+                defined_at = %self.1,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn get_untracked(&self) -> T
     where
         T: Clone,
@@ -140,6 +170,19 @@ impl<T> UntrackedGettableSignal<T> for Memo<T> {
         self.0.get_untracked().unwrap()
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "Memo::with_untracked()",
+            skip_all,
+            fields(
+                id = ?self.0.id,
+                defined_at = %self.1,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn with_untracked<O>(&self, f: impl FnOnce(&T) -> O) -> O {
         // Unwrapping here is fine for the same reasons as <Memo as
         // UntrackedSignal>::get_untracked
@@ -167,6 +210,18 @@ where
     /// # }).dispose();
     /// #
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            name = "Memo::get()",
+            level = "trace",
+            skip_all,
+            fields(
+                id = ?self.0.id,
+                defined_at = %self.1
+            )
+        )
+    )]
     pub fn get(&self) -> T
     where
         T: Clone,
@@ -194,6 +249,19 @@ where
     /// # }).dispose();
     /// #
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            name = "Memo::with()",
+            level = "trace",
+            skip_all,
+            fields(
+                id = ?self.0.id,
+                defined_at = %self.1,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn with<U>(&self, f: impl FnOnce(&T) -> U) -> U {
         // okay to unwrap here, because the value will *always* have initially
         // been set by the effect, synchronously

leptos_reactive/src/resource.rs

@@ -1,3 +1,10 @@
+use crate::{
+    create_effect, create_isomorphic_effect, create_memo, create_signal, queue_microtask,
+    runtime::{with_runtime, RuntimeId},
+    serialization::Serializable,
+    spawn::spawn_local,
+    use_context, Memo, ReadSignal, Scope, ScopeProperty, SuspenseContext, WriteSignal,
+};
 use std::{
     any::Any,
     cell::{Cell, RefCell},
@@ -8,13 +15,6 @@ use std::{
     pin::Pin,
     rc::Rc,
 };
-use crate::{
-    create_effect, create_isomorphic_effect, create_memo, create_signal, queue_microtask,
-    runtime::{with_runtime, RuntimeId},
-    serialization::Serializable,
-    spawn::spawn_local,
-    use_context, Memo, ReadSignal, Scope, ScopeProperty, SuspenseContext, WriteSignal,
-};
 
 /// Creates [Resource](crate::Resource), which is a signal that reflects the
 /// current state of an asynchronous task, allowing you to integrate `async`
@@ -83,6 +83,19 @@ where
 /// output type of the Future to be [Serializable]. If your output cannot be
 /// serialized, or you just want to make sure the [Future] runs locally, use
 /// [create_local_resource_with_initial_value()].
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+            ty = %std::any::type_name::<T>(),
+            signal_ty = %std::any::type_name::<S>(),
+        )
+    )
+)]
+#[track_caller]
 pub fn create_resource_with_initial_value<S, T, Fu>(
     cx: Scope,
     source: impl Fn() -> S + 'static,
@@ -133,6 +146,8 @@ where
         id,
         source_ty: PhantomData,
         out_ty: PhantomData,
+        #[cfg(debug_assertions)]
+        defined_at: std::panic::Location::caller(),
     }
 }
 
@@ -187,6 +202,19 @@ where
 /// Unlike [create_resource_with_initial_value()], this [Future] will always run
 /// on the local system and therefore its output type does not need to be
 /// [Serializable].
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+            ty = %std::any::type_name::<T>(),
+            signal_ty = %std::any::type_name::<S>(),
+        )
+    )
+)]
+#[track_caller]
 pub fn create_local_resource_with_initial_value<S, T, Fu>(
     cx: Scope,
     source: impl Fn() -> S + 'static,
@@ -237,6 +265,8 @@ where
         id,
         source_ty: PhantomData,
         out_ty: PhantomData,
+        #[cfg(debug_assertions)]
+        defined_at: std::panic::Location::caller(),
     }
 }
 
@@ -430,6 +460,8 @@ where
     pub(crate) id: ResourceId,
     pub(crate) source_ty: PhantomData<S>,
     pub(crate) out_ty: PhantomData<T>,
+    #[cfg(debug_assertions)]
+    pub(crate) defined_at: &'static std::panic::Location<'static>,
 }
 
 // Resources
@@ -449,6 +481,8 @@ where
             id: self.id,
             source_ty: PhantomData,
             out_ty: PhantomData,
+            #[cfg(debug_assertions)]
+            defined_at: self.defined_at,
         }
     }
 }
@@ -635,7 +669,9 @@ where
             })
         });
         Box::pin(async move {
-            rx.next().await.expect("failed while trying to resolve Resource serializer")
+            rx.next()
+                .await
+                .expect("failed while trying to resolve Resource serializer")
         })
     }
 }

leptos_reactive/src/runtime.rs

@@ -112,6 +112,7 @@ impl RuntimeId {
         ret
     }
 
+    #[track_caller]
     pub(crate) fn create_signal<T>(self, value: T) -> (ReadSignal<T>, WriteSignal<T>)
     where
         T: Any + 'static,
@@ -127,11 +128,15 @@ impl RuntimeId {
                 runtime: self,
                 id,
                 ty: PhantomData,
+                #[cfg(debug_assertions)]
+                defined_at: std::panic::Location::caller()
             },
             WriteSignal {
                 runtime: self,
                 id,
                 ty: PhantomData,
+                #[cfg(debug_assertions)]
+                defined_at: std::panic::Location::caller()
             },
         )
     }
@@ -150,17 +155,25 @@ impl RuntimeId {
             runtime: self,
             id,
             ty: PhantomData,
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller()
         }
     }
 
+    #[track_caller]
     pub(crate) fn create_effect<T>(self, f: impl Fn(Option<T>) -> T + 'static) -> EffectId
     where
         T: Any + 'static,
     {
+        #[cfg(debug_assertions)]
+        let defined_at = std::panic::Location::caller();
+
         with_runtime(self, |runtime| {
             let effect = Effect {
                 f,
                 value: RefCell::new(None),
+                #[cfg(debug_assertions)]
+                defined_at 
             };
             let id = { runtime.effects.borrow_mut().insert(Rc::new(effect)) };
             id.run::<T>(self);
@@ -168,10 +181,14 @@ impl RuntimeId {
         })
     }
 
+    #[track_caller]
     pub(crate) fn create_memo<T>(self, f: impl Fn(Option<&T>) -> T + 'static) -> Memo<T>
     where
         T: PartialEq + Any + 'static,
     {
+        #[cfg(debug_assertions)]
+        let defined_at = std::panic::Location::caller();
+
         let (read, write) = self.create_signal(None);
 
         self.create_effect(move |_| {
@@ -186,7 +203,11 @@ impl RuntimeId {
             }
         });
 
-        Memo(read)
+        Memo(
+            read,
+            #[cfg(debug_assertions)]
+            defined_at
+        )
     }
 }
 

leptos_reactive/src/signal.rs

@@ -45,15 +45,38 @@ use thiserror::Error;
 /// # }).dispose();
 /// #
 /// ```
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+            ty = %std::any::type_name::<T>()
+        )
+    )
+)]
+#[track_caller]
 pub fn create_signal<T>(cx: Scope, value: T) -> (ReadSignal<T>, WriteSignal<T>) {
     let s = cx.runtime.create_signal(value);
     cx.with_scope_property(|prop| prop.push(ScopeProperty::Signal(s.0.id)));
     s
 }
 
-/// Creates a signal that always contains the most recent value emitted by a [Stream].
+/// Creates a signal that always contains the most recent value emitted by a
+/// [Stream](futures::stream::Stream).
 /// If the stream has not yet emitted a value since the signal was created, the signal's
 /// value will be `None`.
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            scope = ?cx.id,
+        )
+    )
+)]
 pub fn create_signal_from_stream<T>(
     cx: Scope,
     mut stream: impl Stream<Item = T> + Unpin + 'static,
@@ -120,9 +143,24 @@ where
     pub(crate) runtime: RuntimeId,
     pub(crate) id: SignalId,
     pub(crate) ty: PhantomData<T>,
+    #[cfg(debug_assertions)]
+    pub(crate) defined_at: &'static std::panic::Location<'static>,
 }
 
 impl<T> UntrackedGettableSignal<T> for ReadSignal<T> {
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "ReadSignal::get_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn get_untracked(&self) -> T
     where
         T: Clone,
@@ -130,6 +168,19 @@ impl<T> UntrackedGettableSignal<T> for ReadSignal<T> {
         self.with_no_subscription(|v| v.clone())
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "ReadSignal::with_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn with_untracked<O>(&self, f: impl FnOnce(&T) -> O) -> O {
         self.with_no_subscription(f)
     }
@@ -157,6 +208,19 @@ where
     /// assert_eq!(first_char(), 'B');
     /// });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "ReadSignal::with()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn with<U>(&self, f: impl FnOnce(&T) -> U) -> U {
         self.id.with(self.runtime, f)
     }
@@ -184,6 +248,19 @@ where
     /// assert_eq!(count(), 0);
     /// });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "ReadSignal::get()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn get(&self) -> T
     where
         T: Clone,
@@ -219,6 +296,8 @@ impl<T> Clone for ReadSignal<T> {
             runtime: self.runtime,
             id: self.id,
             ty: PhantomData,
+            #[cfg(debug_assertions)]
+            defined_at: self.defined_at,
         }
     }
 }
@@ -298,21 +377,62 @@ where
     pub(crate) runtime: RuntimeId,
     pub(crate) id: SignalId,
     pub(crate) ty: PhantomData<T>,
+    #[cfg(debug_assertions)]
+    pub(crate) defined_at: &'static std::panic::Location<'static>,
 }
 
 impl<T> UntrackedSettableSignal<T> for WriteSignal<T>
 where
     T: 'static,
 {
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "WriteSignal::set_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn set_untracked(&self, new_value: T) {
         self.id
             .update_with_no_effect(self.runtime, |v| *v = new_value);
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "WriteSignal::updated_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn update_untracked(&self, f: impl FnOnce(&mut T)) {
         self.id.update_with_no_effect(self.runtime, f);
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "WriteSignal::update_returning_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn update_returning_untracked<U>(&self, f: impl FnOnce(&mut T) -> U) -> Option<U> {
         self.id.update_with_no_effect(self.runtime, f)
     }
@@ -342,6 +462,19 @@ where
     /// assert_eq!(count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            name = "WriteSignal::update()",
+            level = "trace",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn update(&self, f: impl FnOnce(&mut T)) {
         self.id.update(self.runtime, f);
     }
@@ -367,6 +500,19 @@ where
     /// assert_eq!(count(), 2);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "WriteSignal::update_returning()"
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn update_returning<U>(&self, f: impl FnOnce(&mut T) -> U) -> Option<U> {
         self.id.update(self.runtime, f)
     }
@@ -390,6 +536,19 @@ where
     /// assert_eq!(count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "WriteSignal::set()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn set(&self, new_value: T) {
         self.id.update(self.runtime, |n| *n = new_value);
     }
@@ -401,6 +560,8 @@ impl<T> Clone for WriteSignal<T> {
             runtime: self.runtime,
             id: self.id,
             ty: PhantomData,
+            #[cfg(debug_assertions)]
+            defined_at: self.defined_at,
         }
     }
 }
@@ -460,6 +621,16 @@ where
 /// # }).dispose();
 /// #
 /// ```
+#[cfg_attr(
+    debug_assertions,
+    instrument(
+        level = "trace",
+        skip_all,
+        fields(
+            ty = %std::any::type_name::<T>()
+        )
+    )
+)]
 pub fn create_rw_signal<T>(cx: Scope, value: T) -> RwSignal<T> {
     let s = cx.runtime.create_rw_signal(value);
     cx.with_scope_property(|prop| prop.push(ScopeProperty::Signal(s.id)));
@@ -495,6 +666,8 @@ where
     pub(crate) runtime: RuntimeId,
     pub(crate) id: SignalId,
     pub(crate) ty: PhantomData<T>,
+    #[cfg(debug_assertions)]
+    pub(crate) defined_at: &'static std::panic::Location<'static>,
 }
 
 impl<T> Clone for RwSignal<T> {
@@ -503,6 +676,8 @@ impl<T> Clone for RwSignal<T> {
             runtime: self.runtime,
             id: self.id,
             ty: self.ty,
+            #[cfg(debug_assertions)]
+            defined_at: self.defined_at,
         }
     }
 }
@@ -510,6 +685,19 @@ impl<T> Clone for RwSignal<T> {
 impl<T> Copy for RwSignal<T> {}
 
 impl<T> UntrackedGettableSignal<T> for RwSignal<T> {
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::get_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn get_untracked(&self) -> T
     where
         T: Clone,
@@ -518,21 +706,73 @@ impl<T> UntrackedGettableSignal<T> for RwSignal<T> {
             .with_no_subscription(self.runtime, |v: &T| v.clone())
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::with_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn with_untracked<O>(&self, f: impl FnOnce(&T) -> O) -> O {
         self.id.with_no_subscription(self.runtime, f)
     }
 }
 
 impl<T> UntrackedSettableSignal<T> for RwSignal<T> {
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::set_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn set_untracked(&self, new_value: T) {
         self.id
             .update_with_no_effect(self.runtime, |v| *v = new_value);
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::update_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn update_untracked(&self, f: impl FnOnce(&mut T)) {
         self.id.update_with_no_effect(self.runtime, f);
     }
 
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::update_returning_untracked()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     fn update_returning_untracked<U>(&self, f: impl FnOnce(&mut T) -> U) -> Option<U> {
         self.id.update_with_no_effect(self.runtime, f)
     }
@@ -561,6 +801,19 @@ where
     /// # }).dispose();
     /// #
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::with()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn with<U>(&self, f: impl FnOnce(&T) -> U) -> U {
         self.id.with(self.runtime, f)
     }
@@ -578,7 +831,20 @@ where
     /// assert_eq!(count(), 0);
     /// # }).dispose();
     /// #
-    /// ```
+    /// ```   
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::get()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn get(&self) -> T
     where
         T: Clone,
@@ -603,6 +869,19 @@ where
     /// assert_eq!(count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::update()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn update(&self, f: impl FnOnce(&mut T)) {
         self.id.update(self.runtime, f);
     }
@@ -626,6 +905,19 @@ where
     /// assert_eq!(count(), 2);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::update_returning()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn update_returning<U>(&self, f: impl FnOnce(&mut T) -> U) -> Option<U> {
         self.id.update(self.runtime, f)
     }
@@ -644,6 +936,19 @@ where
     /// assert_eq!(count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::set()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn set(&self, value: T) {
         self.id.update(self.runtime, |n| *n = value);
     }
@@ -664,11 +969,27 @@ where
     /// assert_eq!(read_count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::read_only()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
+    #[track_caller]
     pub fn read_only(&self) -> ReadSignal<T> {
         ReadSignal {
             runtime: self.runtime,
             id: self.id,
             ty: PhantomData,
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
         }
     }
 
@@ -686,11 +1007,27 @@ where
     /// assert_eq!(count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::write_only()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
+    #[track_caller]
     pub fn write_only(&self) -> WriteSignal<T> {
         WriteSignal {
             runtime: self.runtime,
             id: self.id,
             ty: PhantomData,
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
         }
     }
 
@@ -707,22 +1044,53 @@ where
     /// assert_eq!(get_count(), 1);
     /// # }).dispose();
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::split()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
+    #[track_caller]
     pub fn split(&self) -> (ReadSignal<T>, WriteSignal<T>) {
         (
             ReadSignal {
                 runtime: self.runtime,
                 id: self.id,
                 ty: PhantomData,
+                #[cfg(debug_assertions)]
+                defined_at: std::panic::Location::caller(),
             },
             WriteSignal {
                 runtime: self.runtime,
                 id: self.id,
                 ty: PhantomData,
+                #[cfg(debug_assertions)]
+                defined_at: std::panic::Location::caller(),
             },
         )
     }
 
     /// Generates a [Stream] that emits the new value of the signal whenever it changes.
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "RwSignal::to_stream()",
+            skip_all,
+            fields(
+                id = ?self.id,
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn to_stream(&self) -> impl Stream<Item = T>
     where
         T: Clone,

leptos_reactive/src/signal_wrappers_read.rs

@@ -1,5 +1,21 @@
 use crate::{store_value, Memo, ReadSignal, RwSignal, Scope, StoredValue, UntrackedGettableSignal};
 
+/// Helper trait for converting `Fn() -> T` closures into
+/// [`Signal<T>`].
+pub trait IntoSignal<T>: Sized {
+    /// Consumes `self`, returning a [`Signal<T>`].
+    fn derive_signal(self, cx: Scope) -> Signal<T>;
+}
+
+impl<F, T> IntoSignal<T> for F
+where
+    F: Fn() -> T + 'static,
+{
+    fn derive_signal(self, cx: Scope) -> Signal<T> {
+        Signal::derive(cx, self)
+    }
+}
+
 /// A wrapper for any kind of readable reactive signal: a [ReadSignal](crate::ReadSignal),
 /// [Memo](crate::Memo), [RwSignal](crate::RwSignal), or derived signal closure.
 ///
@@ -27,13 +43,22 @@ use crate::{store_value, Memo, ReadSignal, RwSignal, Scope, StoredValue, Untrack
 /// # });
 /// ```
 #[derive(Debug, PartialEq, Eq)]
-pub struct Signal<T>(SignalTypes<T>)
+pub struct Signal<T>
 where
-    T: 'static;
+    T: 'static,
+{
+    inner: SignalTypes<T>,
+    #[cfg(debug_assertions)]
+    defined_at: &'static std::panic::Location<'static>,
+}
 
 impl<T> Clone for Signal<T> {
     fn clone(&self) -> Self {
-        Self(self.0)
+        Self {
+            inner: self.inner,
+            #[cfg(debug_assertions)]
+            defined_at: self.defined_at,
+        }
     }
 }
 
@@ -50,7 +75,7 @@ where
     where
         T: Clone,
     {
-        match &self.0 {
+        match &self.inner {
             SignalTypes::ReadSignal(s) => s.get_untracked(),
             SignalTypes::Memo(m) => m.get_untracked(),
             SignalTypes::DerivedSignal(cx, f) => cx.untrack(|| f.with(|f| f())),
@@ -58,7 +83,7 @@ where
     }
 
     fn with_untracked<O>(&self, f: impl FnOnce(&T) -> O) -> O {
-        match &self.0 {
+        match &self.inner {
             SignalTypes::ReadSignal(s) => s.with_untracked(f),
             SignalTypes::Memo(s) => s.with_untracked(f),
             SignalTypes::DerivedSignal(cx, v_f) => {
@@ -93,11 +118,30 @@ where
     /// assert_eq!(above_3(&double_count), true);
     /// # });
     /// ```
+    #[track_caller]
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            skip_all,
+            fields(
+                cx = ?cx.id
+            )
+        )
+    )]
     pub fn derive(cx: Scope, derived_signal: impl Fn() -> T + 'static) -> Self {
-        Self(SignalTypes::DerivedSignal(
-            cx,
-            store_value(cx, Box::new(derived_signal)),
-        ))
+        let span = ::tracing::Span::current();
+
+        let derived_signal = move || {
+            let _guard = span.enter();
+            derived_signal()
+        };
+
+        Self {
+            inner: SignalTypes::DerivedSignal(cx, store_value(cx, Box::new(derived_signal))),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 
     /// Applies a function to the current value of the signal, and subscribes
@@ -129,8 +173,19 @@ where
     /// assert_eq!(memoized_lower(), "alice");
     /// });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            skip_all,
+            fields(
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn with<U>(&self, f: impl FnOnce(&T) -> U) -> U {
-        match &self.0 {
+        match &self.inner {
             SignalTypes::ReadSignal(s) => s.with(f),
             SignalTypes::Memo(s) => s.with(f),
             SignalTypes::DerivedSignal(_, s) => f(&s.with(|s| s())),
@@ -159,11 +214,22 @@ where
     /// assert_eq!(above_3(&memoized_double_count.into()), true);
     /// # });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            skip_all,
+            fields(
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn get(&self) -> T
     where
         T: Clone,
     {
-        match &self.0 {
+        match &self.inner {
             SignalTypes::ReadSignal(s) => s.get(),
             SignalTypes::Memo(s) => s.get(),
             SignalTypes::DerivedSignal(_, s) => s.with(|s| s()),
@@ -181,20 +247,35 @@ where
 }
 
 impl<T> From<ReadSignal<T>> for Signal<T> {
+    #[track_caller]
     fn from(value: ReadSignal<T>) -> Self {
-        Self(SignalTypes::ReadSignal(value))
+        Self {
+            inner: SignalTypes::ReadSignal(value),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 }
 
 impl<T> From<RwSignal<T>> for Signal<T> {
+    #[track_caller]
     fn from(value: RwSignal<T>) -> Self {
-        Self(SignalTypes::ReadSignal(value.read_only()))
+        Self {
+            inner: SignalTypes::ReadSignal(value.read_only()),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 }
 
 impl<T> From<Memo<T>> for Signal<T> {
+    #[track_caller]
     fn from(value: Memo<T>) -> Self {
-        Self(SignalTypes::Memo(value))
+        Self {
+            inner: SignalTypes::Memo(value),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 }
 
@@ -360,6 +441,18 @@ where
     /// assert_eq!(above_3(&double_count), true);
     /// # });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "MaybeSignal::derive()",
+            skip_all,
+            fields(
+                cx = ?cx.id,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn derive(cx: Scope, derived_signal: impl Fn() -> T + 'static) -> Self {
         Self::Dynamic(Signal::derive(cx, derived_signal))
     }
@@ -396,6 +489,15 @@ where
     /// assert_eq!(static_value(), "Bob");
     /// });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "MaybeSignal::derive()",
+            skip_all,
+            fields(ty = %std::any::type_name::<T>())
+        )
+    )]
     pub fn with<U>(&self, f: impl FnOnce(&T) -> U) -> U {
         match &self {
             Self::Static(value) => f(value),
@@ -427,6 +529,15 @@ where
     /// assert_eq!(above_3(&static_value.into()), true);
     /// # });
     /// ```
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            name = "MaybeSignal::derive()",
+            skip_all,
+            fields(ty = %std::any::type_name::<T>())
+        )
+    )]
     pub fn get(&self) -> T
     where
         T: Clone,

leptos_reactive/src/signal_wrappers_write.rs

@@ -1,5 +1,20 @@
 use crate::{store_value, RwSignal, Scope, StoredValue, WriteSignal};
 
+/// Helper trait for converting `Fn(T)` into [`SignalSetter<T>`].
+pub trait IntoSignalSetter<T>: Sized {
+    /// Consumes `self`, returning [`SignalSetter<T>`].
+    fn mapped_signal_setter(self, cx: Scope) -> SignalSetter<T>;
+}
+
+impl<F, T> IntoSignalSetter<T> for F
+where
+    F: Fn(T) + 'static,
+{
+    fn mapped_signal_setter(self, cx: Scope) -> SignalSetter<T> {
+        SignalSetter::map(cx, self)
+    }
+}
+
 /// A wrapper for any kind of settable reactive signal: a [WriteSignal](crate::WriteSignal),
 /// [RwSignal](crate::RwSignal), or closure that receives a value and sets a signal depending
 /// on it.
@@ -28,19 +43,33 @@ use crate::{store_value, RwSignal, Scope, StoredValue, WriteSignal};
 /// # });
 /// ```
 #[derive(Debug, PartialEq, Eq)]
-pub struct SignalSetter<T>(SignalSetterTypes<T>)
+pub struct SignalSetter<T>
 where
-    T: 'static;
+    T: 'static,
+{
+    inner: SignalSetterTypes<T>,
+    #[cfg(debug_assertions)]
+    defined_at: &'static std::panic::Location<'static>,
+}
 
 impl<T> Clone for SignalSetter<T> {
     fn clone(&self) -> Self {
-        Self(self.0)
+        Self {
+            inner: self.inner,
+            #[cfg(debug_assertions)]
+            defined_at: self.defined_at,
+        }
     }
 }
 
 impl<T: Default + 'static> Default for SignalSetter<T> {
+    #[track_caller]
     fn default() -> Self {
-        Self(SignalSetterTypes::Default)
+        Self {
+            inner: SignalSetterTypes::Default,
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 }
 
@@ -71,11 +100,23 @@ where
     /// assert_eq!(count(), 8);
     /// # });
     /// ```
+    #[track_caller]
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            skip_all,
+            fields(
+                cx = ?cx.id,
+            )
+        )
+    )]
     pub fn map(cx: Scope, mapped_setter: impl Fn(T) + 'static) -> Self {
-        Self(SignalSetterTypes::Mapped(
-            cx,
-            store_value(cx, Box::new(mapped_setter)),
-        ))
+        Self {
+            inner: SignalSetterTypes::Mapped(cx, store_value(cx, Box::new(mapped_setter))),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 
     /// Calls the setter function with the given value.
@@ -98,8 +139,19 @@ where
     /// set_to_4(&set_double_count);
     /// assert_eq!(count(), 8);
     /// # });
+    #[cfg_attr(
+        debug_assertions,
+        instrument(
+            level = "trace",
+            skip_all,
+            fields(
+                defined_at = %self.defined_at,
+                ty = %std::any::type_name::<T>()
+            )
+        )
+    )]
     pub fn set(&self, value: T) {
-        match &self.0 {
+        match &self.inner {
             SignalSetterTypes::Write(s) => s.set(value),
             SignalSetterTypes::Mapped(_, s) => s.with(|s| s(value)),
             SignalSetterTypes::Default => {}
@@ -108,14 +160,24 @@ where
 }
 
 impl<T> From<WriteSignal<T>> for SignalSetter<T> {
+    #[track_caller]
     fn from(value: WriteSignal<T>) -> Self {
-        Self(SignalSetterTypes::Write(value))
+        Self {
+            inner: SignalSetterTypes::Write(value),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 }
 
 impl<T> From<RwSignal<T>> for SignalSetter<T> {
+    #[track_caller]
     fn from(value: RwSignal<T>) -> Self {
-        Self(SignalSetterTypes::Write(value.write_only()))
+        Self {
+            inner: SignalSetterTypes::Write(value.write_only()),
+            #[cfg(debug_assertions)]
+            defined_at: std::panic::Location::caller(),
+        }
     }
 }
 

leptos_server/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "leptos_server"
-version = "0.1.0-beta"
+version.workspace = true
 edition = "2021"
 authors = ["Greg Johnston"]
 license = "MIT"
@@ -8,8 +8,8 @@ repository = "https://github.com/gbj/leptos"
 description = "RPC for the Leptos web framework."
 
 [dependencies]
-leptos_dom = { path = "../leptos_dom", default-features = false, version = "0.1.0-beta" }
-leptos_reactive = { path = "../leptos_reactive", default-features = false, version = "0.1.0-beta" }
+leptos_dom.workspace = true
+leptos_reactive.workspace = true
 form_urlencoded = "1"
 gloo-net = "0.2"
 lazy_static = "1"
@@ -26,7 +26,7 @@ proc-macro2 = "1.0.47"
 ciborium = "0.2.0"
 
 [dev-dependencies]
-leptos = { path = "../leptos", default-features = false }
+leptos.workspace = true
 
 [features]
 csr = [

meta/Cargo.toml

@@ -9,7 +9,8 @@ description = "Tools to set HTML metadata in the Leptos web framework."
 
 [dependencies]
 cfg-if = "1"
-leptos = { path = "../leptos", version = "0.1.0-beta", default-features = false }
+leptos.workspace = true
+tracing = "0.1"
 typed-builder = "0.11"
 
 [dependencies.web-sys]
@@ -17,11 +18,12 @@ version = "0.3"
 features = ["HtmlLinkElement", "HtmlMetaElement", "HtmlTitleElement"]
 
 [features]
-default = ["csr"]
-csr = ["leptos/csr"]
-hydrate = ["leptos/hydrate"]
-ssr = ["leptos/ssr"]
-stable = ["leptos/stable"]
+default = []
+csr = ["leptos/csr", "leptos/tracing"]
+hydrate = ["leptos/hydrate", "leptos/tracing"]
+ssr = ["leptos/ssr", "leptos/tracing"]
+stable = ["leptos/stable", "leptos/tracing"]
 
 [package.metadata.cargo-all-features]
 denylist = ["stable"]
+skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]

meta/src/lib.rs

@@ -36,14 +36,26 @@
 //!
 //! ```
 
-use std::{fmt::Debug, rc::Rc};
+use cfg_if::cfg_if;
+use std::{
+    cell::{Cell, RefCell},
+    collections::HashMap,
+    fmt::Debug,
+    rc::Rc,
+};
 
 use leptos::{leptos_dom::debug_warn, *};
 
+mod link;
 mod meta_tags;
+mod script;
+mod style;
 mod stylesheet;
 mod title;
+pub use link::*;
 pub use meta_tags::*;
+pub use script::*;
+pub use style::*;
 pub use stylesheet::*;
 pub use title::*;
 
@@ -51,11 +63,83 @@ pub use title::*;
 ///
 /// This should generally by provided somewhere in the root of your application using
 /// [provide_meta_context].
-#[derive(Debug, Clone, Default)]
+#[derive(Clone, Default)]
 pub struct MetaContext {
     pub(crate) title: TitleContext,
-    pub(crate) stylesheets: StylesheetContext,
-    pub(crate) meta_tags: MetaTagsContext,
+    pub(crate) tags: MetaTagsContext,
+}
+
+/// Manages all of the element created by components.
+#[derive(Clone, Default)]
+pub(crate) struct MetaTagsContext {
+    next_id: Rc<Cell<MetaTagId>>,
+    #[allow(clippy::type_complexity)]
+    els: Rc<RefCell<HashMap<String, (HtmlElement<AnyElement>, Scope, Option<web_sys::Element>)>>>,
+}
+
+impl MetaTagsContext {
+    #[cfg(feature = "ssr")]
+    pub fn as_string(&self) -> String {
+        self.els
+            .borrow()
+            .iter()
+            .map(|(_, (builder_el, cx, _))| builder_el.clone().into_view(*cx).render_to_string(*cx))
+            .collect()
+    }
+
+    pub fn register(&self, cx: Scope, id: String, builder_el: HtmlElement<AnyElement>) {
+        cfg_if! {
+            if #[cfg(any(feature = "csr", feature = "hydrate"))] {
+                use leptos::document;
+
+                let element_to_hydrate = document()
+                    .get_element_by_id(&id);
+
+                let el = element_to_hydrate.unwrap_or_else({
+                    let builder_el = builder_el.clone();
+                    move || {
+                        let head = document().head().unwrap_throw();
+                        head
+                            .append_child(&builder_el)
+                            .unwrap_throw();
+
+                        (*builder_el).clone().unchecked_into()
+                    }
+                });
+
+                on_cleanup(cx, {
+                    let el = el.clone();
+                    let els = self.els.clone();
+                    let id = id.clone();
+                    move || {
+                        let head = document().head().unwrap_throw();
+                        _ = head.remove_child(&el);
+                        els.borrow_mut().remove(&id);
+                    }
+                });
+
+                self
+                    .els
+                    .borrow_mut()
+                    .insert(id, (builder_el.into_any(), cx, Some(el)));
+
+            } else {
+                self.els.borrow_mut().insert(id, (builder_el, cx, None));
+            }
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
+struct MetaTagId(usize);
+
+impl MetaTagsContext {
+    fn get_next_id(&self) -> MetaTagId {
+        let current_id = self.next_id.get();
+        let next_id = MetaTagId(current_id.0 + 1);
+        self.next_id.set(next_id);
+        next_id
+    }
 }
 
 /// Provides a [MetaContext], if there is not already one provided. This ensures that you can provide it
@@ -98,7 +182,7 @@ impl MetaContext {
         Default::default()
     }
 
-    #[cfg(not(any(feature = "csr", feature = "hydrate")))]
+    #[cfg(feature = "ssr")]
     /// Converts the existing metadata tags into HTML that can be injected into the document head.
     ///
     /// This should be called *after* the app’s component tree has been rendered into HTML, so that
@@ -123,14 +207,15 @@ impl MetaContext {
     ///   // `app` contains only the body content w/ hydration stuff, not the meta tags
     ///   assert_eq!(
     ///      app.into_view(cx).render_to_string(cx),
-    ///      "<main id=\"_0-1\"><leptos-unit leptos id=_0-2c></leptos-unit><leptos-unit leptos id=_0-3c></leptos-unit><p id=\"_0-4\">Some text</p></main>"
+    ///      "<main id=\"_0-1\"><leptos-unit leptos id=_0-2c></leptos-unit><leptos-unit leptos id=_0-4c></leptos-unit><p id=\"_0-5\">Some text</p></main>"
     ///   );
     ///   // `MetaContext::dehydrate()` gives you HTML that should be in the `<head>`
-    ///   assert_eq!(use_head(cx).dehydrate(), r#"<title>my title</title><link rel="stylesheet" href="/style.css">"#)
+    ///   assert_eq!(use_head(cx).dehydrate(), r#"<title>my title</title><link id="leptos-link-1" href="/style.css" rel="stylesheet" leptos-hk="_0-3"/>"#)
     /// });
     /// # }
     /// ```
     pub fn dehydrate(&self) -> String {
+        let prev_key = HydrationCtx::peek();
         let mut tags = String::new();
 
         // Title
@@ -139,12 +224,9 @@ impl MetaContext {
             tags.push_str(&title);
             tags.push_str("</title>");
         }
-        // Stylesheets
-        tags.push_str(&self.stylesheets.as_string());
-
-        // Meta tags
-        tags.push_str(&self.meta_tags.as_string());
+        tags.push_str(&self.tags.as_string());
 
+        HydrationCtx::continue_from(prev_key);
         tags
     }
 }

meta/src/link.rs

@@ -0,0 +1,109 @@
+use crate::use_head;
+use leptos::*;
+
+/// Injects an [HTMLLinkElement](https://developer.mozilla.org/en-US/docs/Web/API/HTMLLinkElement) into the document
+/// head, accepting any of the valid attributes for that tag.
+/// ```
+/// use leptos::*;
+/// use leptos_meta::*;
+///
+/// #[component]
+/// fn MyApp(cx: Scope) -> impl IntoView {
+///   provide_meta_context(cx);
+///
+///   view! { cx,
+///     <main>
+///       <Link rel="preload"
+///         href="myFont.woff2"
+///         as_="font"
+///         type_="font/woff2"
+///         crossorigin="anonymous"
+///       />
+///     </main>
+///   }
+/// }
+/// ```
+#[component(transparent)]
+pub fn Link(
+    cx: Scope,
+    /// The [`id`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-id) attribute.
+    #[prop(optional, into)]
+    id: Option<String>,
+    /// The [`as`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-as) attribute.
+    #[prop(optional, into)]
+    as_: Option<String>,
+    /// The [`crossorigin`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-crossorigin) attribute.
+    #[prop(optional, into)]
+    crossorigin: Option<String>,
+    /// The [`disabled`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-disabled) attribute.
+    #[prop(optional, into)]
+    disabled: Option<bool>,
+    /// The [`fetchpriority`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-fetchpriority) attribute.
+    #[prop(optional, into)]
+    fetchpriority: Option<String>,
+    /// The [`href`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-href) attribute.
+    #[prop(optional, into)]
+    href: Option<String>,
+    /// The [`hreflang`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-hreflang) attribute.
+    #[prop(optional, into)]
+    hreflang: Option<String>,
+    /// The [`imagesizes`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-imagesizes) attribute.
+    #[prop(optional, into)]
+    imagesizes: Option<String>,
+    /// The [`imagesrcset`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-imagesrcset) attribute.
+    #[prop(optional, into)]
+    imagesrcset: Option<String>,
+    /// The [`integrity`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-integrity) attribute.
+    #[prop(optional, into)]
+    integrity: Option<String>,
+    /// The [`media`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-media) attribute.
+    #[prop(optional, into)]
+    media: Option<String>,
+    /// The [`prefetch`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-prefetch) attribute.
+    #[prop(optional, into)]
+    prefetch: Option<String>,
+    /// The [`referrerpolicy`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-referrerpolicy) attribute.
+    #[prop(optional, into)]
+    referrerpolicy: Option<String>,
+    /// The [`rel`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-rel) attribute.
+    #[prop(optional, into)]
+    rel: Option<String>,
+    /// The [`sizes`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-sizes) attribute.
+    #[prop(optional, into)]
+    sizes: Option<String>,
+    /// The [`title`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-title) attribute.
+    #[prop(optional, into)]
+    title: Option<String>,
+    /// The [`type`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-type) attribute.
+    #[prop(optional, into)]
+    type_: Option<String>,
+    /// The [`blocking`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/link#attr-blocking) attribute.
+    #[prop(optional, into)]
+    blocking: Option<String>,
+) -> impl IntoView {
+    let meta = use_head(cx);
+    let next_id = meta.tags.get_next_id();
+    let id = id.unwrap_or_else(|| format!("leptos-link-{}", next_id.0));
+
+    let builder_el = leptos::link(cx)
+        .attr("id", &id)
+        .attr("as_", as_)
+        .attr("crossorigin", crossorigin)
+        .attr("disabled", disabled.unwrap_or(false))
+        .attr("fetchpriority", fetchpriority)
+        .attr("href", href)
+        .attr("hreflang", hreflang)
+        .attr("imagesizes", imagesizes)
+        .attr("imagesrcset", imagesrcset)
+        .attr("integrity", integrity)
+        .attr("media", media)
+        .attr("prefetch", prefetch)
+        .attr("referrerpolicy", referrerpolicy)
+        .attr("rel", rel)
+        .attr("sizes", sizes)
+        .attr("title", title)
+        .attr("type", type_)
+        .attr("blocking", blocking);
+
+    meta.tags.register(cx, id, builder_el.into_any());
+}

meta/src/meta_tags.rs

@@ -1,73 +1,7 @@
-use cfg_if::cfg_if;
 use leptos::{component, IntoView, Scope};
-use std::{
-    cell::{Cell, RefCell},
-    collections::HashMap,
-    rc::Rc,
-};
 
 use crate::{use_head, TextProp};
 
-/// Manages all of the `<meta>` elements set by [Meta] components.
-#[derive(Clone, Default, Debug)]
-pub struct MetaTagsContext {
-    next_id: Cell<MetaTagId>,
-    #[allow(clippy::type_complexity)]
-    els: Rc<RefCell<HashMap<MetaTagId, (Option<MetaTag>, Option<web_sys::HtmlMetaElement>)>>>,
-}
-
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
-struct MetaTagId(usize);
-
-impl MetaTagsContext {
-    fn get_next_id(&self) -> MetaTagId {
-        let current_id = self.next_id.get();
-        let next_id = MetaTagId(current_id.0 + 1);
-        self.next_id.set(next_id);
-        next_id
-    }
-}
-
-#[derive(Clone, Debug)]
-enum MetaTag {
-    Charset(TextProp),
-    HttpEquiv {
-        http_equiv: TextProp,
-        content: Option<TextProp>,
-    },
-    Name {
-        name: TextProp,
-        content: TextProp,
-    },
-}
-
-impl MetaTagsContext {
-    /// Converts the set of `<meta>` elements into an HTML string that can be injected into the `<head>`.
-    pub fn as_string(&self) -> String {
-        self.els
-            .borrow()
-            .iter()
-            .filter_map(|(id, (tag, _))| {
-				tag.as_ref().map(|tag| {
-					let id = id.0;
-
-					match tag {
-						MetaTag::Charset(charset) => format!(r#"<meta charset="{}" data-leptos-meta="{id}">"#, charset.get()),
-						MetaTag::HttpEquiv { http_equiv, content } => {
-							if let Some(content) = &content {
-								format!(r#"<meta http-equiv="{}" content="{}" data-leptos-meta="{id}">"#, http_equiv.get(), content.get())
-							} else {
-								format!(r#"<meta http-equiv="{}" data-leptos-meta="{id}">"#, http_equiv.get())
-							}
-						},
-						MetaTag::Name { name, content } => format!(r#"<meta name="{}" content="{}" data-leptos-meta="{id}">"#, name.get(), content.get()),
-					}
-				})
-			})
-            .collect()
-    }
-}
-
 /// Injects an [HTMLMetaElement](https://developer.mozilla.org/en-US/docs/Web/API/HTMLMetaElement) into the document
 /// head to set metadata
 ///
@@ -104,89 +38,15 @@ pub fn Meta(
     #[prop(optional, into)]
     content: Option<TextProp>,
 ) -> impl IntoView {
-    let tag = match (charset, name, http_equiv, content) {
-		(Some(charset), _, _, _) => MetaTag::Charset(charset),
-		(_, _, Some(http_equiv), content) => MetaTag::HttpEquiv { http_equiv, content },
-		(_, Some(name), _, Some(content)) => MetaTag::Name { name, content },
-		_ => panic!("<Meta/> tag expects either `charset`, `http_equiv`, or `name` and `content` to be set.")
-	};
+    let meta = use_head(cx);
+    let next_id = meta.tags.get_next_id();
+    let id = format!("leptos-link-{}", next_id.0);
 
-    cfg_if! {
-        if #[cfg(any(feature = "csr", feature = "hydrate"))] {
-            use leptos::{document, JsCast, UnwrapThrowExt, create_effect};
+    let builder_el = leptos::meta(cx)
+        .attr("charset", move || charset.as_ref().map(|v| v.get()))
+        .attr("name", move || name.as_ref().map(|v| v.get()))
+        .attr("http-equiv", move || http_equiv.as_ref().map(|v| v.get()))
+        .attr("content", move || content.as_ref().map(|v| v.get()));
 
-            let meta = use_head(cx);
-            let meta_tags = meta.meta_tags;
-            let id = meta_tags.get_next_id();
-
-            let el = if let Ok(Some(el)) = document().query_selector(&format!("[data-leptos-meta='{}']", id.0)) {
-                el
-            } else {
-                document().create_element("meta").unwrap_throw()
-            };
-
-            match tag {
-                MetaTag::Charset(charset) => {
-                    create_effect(cx, {
-                        let el = el.clone();
-                        move |_| {
-                            _ = el.set_attribute("charset", &charset.get());
-                        }
-                    })
-                },
-                MetaTag::HttpEquiv { http_equiv, content } => {
-                    create_effect(cx, {
-                        let el = el.clone();
-                        move |_| {
-                            _ = el.set_attribute("http-equiv", &http_equiv.get());
-                        }
-                    });
-                    if let Some(content) = content {
-                        create_effect(cx, {
-                            let el = el.clone();
-                            move |_| {
-                                _ = el.set_attribute("content", &content.get());
-                            }
-                        });
-                    }
-                },
-                MetaTag::Name { name, content } => {
-                    create_effect(cx, {
-                        let el = el.clone();
-                        move |_| {
-                            _ = el.set_attribute("name", &name.get());
-                        }
-                    });
-                    create_effect(cx, {
-                        let el = el.clone();
-                        move |_| {
-                            _ = el.set_attribute("content", &content.get());
-                        }
-                    });
-                },
-            }
-
-            // add to head
-            let head = document()
-                .query_selector("head")
-                .unwrap_throw()
-                .unwrap_throw();
-            head.append_child(&el)
-                .unwrap_throw();
-
-            leptos::on_cleanup(cx, {
-                let el = el.clone();
-                move || {
-                    head.remove_child(&el);
-                }
-            });
-
-            // add to meta tags
-            meta_tags.els.borrow_mut().insert(id, (None, Some(el.unchecked_into())));
-        } else {
-            let meta = use_head(cx);
-            let meta_tags = meta.meta_tags;
-            meta_tags.els.borrow_mut().insert(meta_tags.get_next_id(), (Some(tag), None));
-        }
-    }
+    meta.tags.register(cx, id, builder_el.into_any());
 }

meta/src/script.rs

@@ -0,0 +1,98 @@
+use crate::use_head;
+use leptos::*;
+
+/// Injects an [HTMLScriptElement](https://developer.mozilla.org/en-US/docs/Web/API/HTMLScriptElement) into the document
+/// head, accepting any of the valid attributes for that tag.
+/// ```
+/// use leptos::*;
+/// use leptos_meta::*;
+///
+/// #[component]
+/// fn MyApp(cx: Scope) -> impl IntoView {
+///   provide_meta_context(cx);
+///
+///   view! { cx,
+///     <main>
+///       <Script>
+///         "console.log('Hello, world!');"
+///       </Script>
+///     </main>
+///   }
+/// }
+/// ```
+#[component(transparent)]
+pub fn Script(
+    cx: Scope,
+    /// An ID for the `<script>` tag.
+    #[prop(optional, into)]
+    id: Option<String>,
+    /// The [`async`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-async) attribute.
+    #[prop(optional, into)]
+    async_: Option<String>,
+    /// The [`crossorigin`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-crossorigin) attribute.
+    #[prop(optional, into)]
+    crossorigin: Option<String>,
+    /// The [`defer`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-defer) attribute.
+    #[prop(optional, into)]
+    defer: Option<String>,
+    /// The [`fetchpriority `](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-fetchpriority ) attribute.
+    #[prop(optional, into)]
+    fetchpriority: Option<String>,
+    /// The [`integrity`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-integrity) attribute.
+    #[prop(optional, into)]
+    integrity: Option<String>,
+    /// The [`nomodule`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-nomodule) attribute.
+    #[prop(optional, into)]
+    nomodule: Option<String>,
+    /// The [`nonce`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-nonce) attribute.
+    #[prop(optional, into)]
+    nonce: Option<String>,
+    /// The [`referrerpolicy`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-referrerpolicy) attribute.
+    #[prop(optional, into)]
+    referrerpolicy: Option<String>,
+    /// The [`src`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-src) attribute.
+    #[prop(optional, into)]
+    src: Option<String>,
+    /// The [`type`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-type) attribute.
+    #[prop(optional, into)]
+    type_: Option<String>,
+    /// The [`blocking`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script#attr-blocking) attribute.
+    #[prop(optional, into)]
+    blocking: Option<String>,
+    /// The content of the `<script>` tag.
+    #[prop(optional)]
+    children: Option<Box<dyn FnOnce(Scope) -> Fragment>>,
+) -> impl IntoView {
+    let meta = use_head(cx);
+    let next_id = meta.tags.get_next_id();
+    let id = id.unwrap_or_else(|| format!("leptos-link-{}", next_id.0));
+
+    let builder_el = leptos::script(cx)
+        .attr("id", &id)
+        .attr("async", async_)
+        .attr("crossorigin", crossorigin)
+        .attr("defer", defer)
+        .attr("fetchpriority ", fetchpriority)
+        .attr("integrity", integrity)
+        .attr("nomodule", nomodule)
+        .attr("nonce", nonce)
+        .attr("referrerpolicy", referrerpolicy)
+        .attr("src", src)
+        .attr("type", type_)
+        .attr("blocking", blocking);
+    let builder_el = if let Some(children) = children {
+        let frag = children(cx);
+        let mut script = String::new();
+        for node in frag.nodes {
+            match node {
+                View::Text(text) => script.push_str(&text.content),
+                _ => leptos::warn!("Only text nodes are supported as children of <Script/>."),
+            }
+        }
+        builder_el.child(script)
+    } else {
+        builder_el
+    };
+
+    meta.tags.register(cx, id, builder_el.into_any());
+}

meta/src/style.rs

@@ -0,0 +1,70 @@
+use crate::use_head;
+use leptos::*;
+
+/// Injects an [HTMLStyleElement](https://developer.mozilla.org/en-US/docs/Web/API/HTMLStyleElement) into the document
+/// head, accepting any of the valid attributes for that tag.
+/// ```
+/// use leptos::*;
+/// use leptos_meta::*;
+///
+/// #[component]
+/// fn MyApp(cx: Scope) -> impl IntoView {
+///   provide_meta_context(cx);
+///
+///   view! { cx,
+///     <main>
+///       <Style>
+///         "body { font-weight: bold; }"
+///       </Style>
+///     </main>
+///   }
+/// }
+/// ```
+#[component(transparent)]
+pub fn Style(
+    cx: Scope,
+    /// An ID for the `<script>` tag.
+    #[prop(optional, into)]
+    id: Option<String>,
+    /// The [`media`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/style#attr-media) attribute.
+    #[prop(optional, into)]
+    media: Option<String>,
+    /// The [`nonce`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/style#attr-nonce) attribute.
+    #[prop(optional, into)]
+    nonce: Option<String>,
+    /// The [`title`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/style#attr-title) attribute.
+    #[prop(optional, into)]
+    title: Option<String>,
+    /// The [`blocking`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/style#attr-blocking) attribute.
+    #[prop(optional, into)]
+    blocking: Option<String>,
+    /// The content of the `<style>` tag.
+    #[prop(optional)]
+    children: Option<Box<dyn FnOnce(Scope) -> Fragment>>,
+) -> impl IntoView {
+    let meta = use_head(cx);
+    let next_id = meta.tags.get_next_id();
+    let id = id.unwrap_or_else(|| format!("leptos-link-{}", next_id.0));
+
+    let builder_el = leptos::style(cx)
+        .attr("id", &id)
+        .attr("media", media)
+        .attr("nonce", nonce)
+        .attr("title", title)
+        .attr("blocking", blocking);
+    let builder_el = if let Some(children) = children {
+        let frag = children(cx);
+        let mut style = String::new();
+        for node in frag.nodes {
+            match node {
+                View::Text(text) => style.push_str(&text.content),
+                _ => leptos::warn!("Only text nodes are supported as children of <Style/>."),
+            }
+        }
+        builder_el.child(style)
+    } else {
+        builder_el
+    };
+
+    meta.tags.register(cx, id, builder_el.into_any());
+}

meta/src/stylesheet.rs

@@ -1,51 +1,5 @@
-use crate::use_head;
-use cfg_if::cfg_if;
+use crate::{Link, LinkProps};
 use leptos::*;
-use std::{
-    cell::{Cell, RefCell},
-    collections::HashMap,
-    rc::Rc,
-};
-
-/// Manages all of the stylesheets set by [Stylesheet] components.
-#[derive(Clone, Default, Debug)]
-pub struct StylesheetContext {
-    #[allow(clippy::type_complexity)]
-    // key is (id, href)
-    els: Rc<RefCell<HashMap<StyleSheetData, Option<web_sys::HtmlLinkElement>>>>,
-    next_id: Rc<Cell<StylesheetId>>,
-}
-
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
-struct StylesheetId(usize);
-
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-struct StyleSheetData {
-    id: String,
-    href: String,
-}
-
-impl StylesheetContext {
-    fn get_next_id(&self) -> StylesheetId {
-        let current_id = self.next_id.get();
-        let next_id = StylesheetId(current_id.0 + 1);
-        self.next_id.set(next_id);
-        next_id
-    }
-}
-
-impl StylesheetContext {
-    /// Converts the set of stylesheets into an HTML string that can be injected into the `<head>`.
-    pub fn as_string(&self) -> String {
-        self.els
-            .borrow()
-            .iter()
-            .map(|(StyleSheetData { id, href }, _)| {
-                format!(r#"<link rel="stylesheet" id="{id}" href="{href}">"#)
-            })
-            .collect()
-    }
-}
 
 /// Injects an [HTMLLinkElement](https://developer.mozilla.org/en-US/docs/Web/API/HTMLLinkElement) into the document
 /// head that loads a stylesheet from the URL given by the `href` property.
@@ -75,50 +29,13 @@ pub fn Stylesheet(
     #[prop(optional, into)]
     id: Option<String>,
 ) -> impl IntoView {
-    let meta = use_head(cx);
-    let stylesheets = &meta.stylesheets;
-    let next_id = stylesheets.get_next_id();
-    let id = id.unwrap_or_else(|| format!("leptos-style-{}", next_id.0));
-    let key = StyleSheetData { id, href };
-
-    cfg_if! {
-        if #[cfg(any(feature = "csr", feature = "hydrate"))] {
-            use leptos::document;
-
-            let element_to_hydrate = document().get_element_by_id(&key.id);
-
-            let el = element_to_hydrate.unwrap_or_else(|| {
-                let el = document().create_element("link").unwrap_throw();
-                el.set_attribute("rel", "stylesheet").unwrap_throw();
-                el.set_attribute("id", &key.id).unwrap_throw();
-                el.set_attribute("href", &key.href).unwrap_throw();
-                let head = document().head().unwrap_throw();
-                head
-                    .append_child(el.unchecked_ref())
-                    .unwrap_throw();
-
-                el
-            });
-
-            on_cleanup(cx, {
-                let el = el.clone();
-                let els = meta.stylesheets.els.clone();
-                let key = key.clone();
-                move || {
-                    let head = document().head().unwrap_throw();
-                    _ = head.remove_child(&el);
-                    els.borrow_mut().remove(&key);
-                }
-            });
-
-            meta.stylesheets
-                .els
-                .borrow_mut()
-                .insert(key, Some(el.unchecked_into()));
-
-        } else {
-            let meta = use_head(cx);
-            meta.stylesheets.els.borrow_mut().insert(key, None);
+    if let Some(id) = id {
+        view! { cx,
+            <Link id rel="stylesheet" href/>
+        }
+    } else {
+        view! { cx,
+            <Link rel="stylesheet" href/>
         }
     }
 }

router/Cargo.toml

@@ -8,7 +8,7 @@ repository = "https://github.com/gbj/leptos"
 description = "Router for the Leptos web framework."
 
 [dependencies]
-leptos = { path = "../leptos", version = "0.1.0-beta", default-features = false }
+leptos.workspace = true
 cfg-if = "1"
 common_macros = "0.1"
 gloo-net = "0.2"
@@ -53,7 +53,7 @@ features = [
 ]
 
 [features]
-default = ["csr"]
+default = []
 csr = ["leptos/csr"]
 hydrate = ["leptos/hydrate"]
 ssr = ["leptos/ssr", "dep:url", "dep:regex"]
@@ -62,3 +62,4 @@ stable = ["leptos/stable"]
 [package.metadata.cargo-all-features]
 # No need to test optional dependencies as they are enabled by the ssr feature
 denylist = ["url", "regex", "stable"]
+skip_feature_sets = [["csr", "ssr"], ["csr", "hydrate"], ["ssr", "hydrate"]]

router/src/components/form.rs

@@ -36,7 +36,7 @@ pub fn Form<A>(
     #[prop(optional)]
     on_response: Option<Rc<dyn Fn(&web_sys::Response)>>,
     /// Component children; should include the HTML of the form elements.
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     A: ToHref + 'static,
@@ -134,7 +134,7 @@ pub fn ActionForm<I, O>(
     /// manually using [leptos_server::Action::using_server_fn].
     action: Action<I, Result<O, ServerFnError>>,
     /// Component children; should include the HTML of the form elements.
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     I: Clone + ServerFn + 'static,
@@ -208,7 +208,7 @@ pub fn MultiActionForm<I, O>(
     /// manually using [leptos_server::Action::using_server_fn].
     action: MultiAction<I, Result<O, ServerFnError>>,
     /// Component children; should include the HTML of the form elements.
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     I: Clone + ServerFn + 'static,

router/src/components/link.rs

@@ -58,7 +58,7 @@ pub fn A<H>(
     #[prop(optional, into)]
     class: Option<MaybeSignal<String>>,
     /// The nodes or elements to be shown inside the link.
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     H: ToHref + 'static,

router/src/components/route.rs

@@ -26,7 +26,7 @@ pub fn Route<E, F, P>(
     view: F,
     /// `children` may be empty or include nested routes.
     #[prop(optional)]
-    children: Option<Box<dyn Fn(Scope) -> Fragment>>,
+    children: Option<Box<dyn FnOnce(Scope) -> Fragment>>,
 ) -> impl IntoView
 where
     E: IntoView,

router/src/components/router.rs

@@ -32,7 +32,7 @@ pub fn Router(
     /// The `<Router/>` should usually wrap your whole page. It can contain
     /// any elements, and should include a [Routes](crate::Routes) component somewhere
     /// to define and display [Route](crate::Route)s.
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView {
     // create a new RouterContext and provide it to every component beneath the router
     let router = RouterContext::new(cx, base, fallback);
@@ -104,10 +104,10 @@ impl RouterContext {
                     value: base_path.to_string(),
                     replace: true,
                     scroll: false,
-                    state: State(None)
+                    state: State(None),
                 });
             }
-		}
+        }
 
         // the current URL
         let (reference, set_reference) = create_signal(cx, source.with(|s| s.value.clone()));

router/src/components/routes.rs

@@ -22,7 +22,7 @@ use crate::{
 pub fn Routes(
     cx: Scope,
     #[prop(optional)] base: Option<String>,
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView {
     let router = use_context::<RouterContext>(cx).unwrap_or_else(|| {
         log::warn!("<Routes/> component should be nested within a <Router/>.");

router/src/history/params.rs

@@ -118,7 +118,7 @@ where
             Some(value) => match T::from_str(value) {
                 Ok(value) => Ok(Some(value)),
                 Err(e) => {
-                    eprintln!("{}", e);
+                    eprintln!("{e}");
                     Err(ParamsError::Params(Rc::new(e)))
                 }
             },