`children` should take `FnOnce(Scope) -> Fragment`, to ease need of cloning etc.

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,
@@ -58,7 +58,7 @@ pub fn Suspense<F, E>(
     /// Returns a fallback UI that will be shown while `async` [Resources](leptos_reactive::Resource) are still loading.
     fallback: F,
     /// Children will be displayed once all `async` [Resources](leptos_reactive::Resource) have resolved.
-    children: Box<dyn Fn(Scope) -> Fragment>,
+    children: Box<dyn FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     F: Fn() -> E + 'static,
@@ -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 FnOnce(Scope) -> Fragment>,
 ) -> impl IntoView
 where
     F: Fn() -> E + 'static,
@@ -98,6 +98,6 @@ where
                 }
                 frag
             }))
-            .build()
+            .build(),
     )
-}
+}

leptos_macro/src/lib.rs

@@ -358,12 +358,12 @@ 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>

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/>.");