From 94f6294c0a1130fa37fa1f5f3ed9c623dc124b61 Mon Sep 17 00:00:00 2001
From: Ben Merritt <blm768@gmail.com>
Date: Thu, 6 Jun 2019 21:37:57 -0700
Subject: [PATCH] Prevent callbacks from being destroyed too early

---
 src/platform_impl/web_sys/event_loop.rs | 7 +++++--
 src/platform_impl/web_sys/window.rs     | 5 +++--
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/platform_impl/web_sys/event_loop.rs b/src/platform_impl/web_sys/event_loop.rs
index 78a70f01..62bbd82a 100644
--- a/src/platform_impl/web_sys/event_loop.rs
+++ b/src/platform_impl/web_sys/event_loop.rs
@@ -259,7 +259,7 @@ fn add_event<T: 'static, E, F>(
 {
     let elrs = elrs.clone();
 
-    target.add_event_listener_with_callback(event, Closure::wrap(Box::new(move |event: E| {
+    let closure = Closure::wrap(Box::new(move |event: E| {
         // Don't capture the event if the events loop has been destroyed
         match &*elrs.runner.borrow() {
             Some(ref runner) if runner.control == ControlFlow::Exit => return,
@@ -272,7 +272,10 @@ fn add_event<T: 'static, E, F>(
         event_ref.cancel_bubble();
 
         handler(&elrs, event);
-    }) as Box<FnMut(E)>).as_ref().unchecked_ref());
+    }) as Box<FnMut(E)>);
+
+    target.add_event_listener_with_callback(event, &closure.as_ref().unchecked_ref());
+    closure.forget(); // TODO: don't leak this.
 }
 
 impl<T> ELRShared<T> {
diff --git a/src/platform_impl/web_sys/window.rs b/src/platform_impl/web_sys/window.rs
index 5a41c5f9..684c580c 100644
--- a/src/platform_impl/web_sys/window.rs
+++ b/src/platform_impl/web_sys/window.rs
@@ -69,12 +69,13 @@ impl Window {
         let runner = target.runner.clone();
         let redraw = Box::new(move || {
             let runner = runner.clone();
-            window().request_animation_frame(Closure::wrap(Box::new(move |_: f64| {
+            let closure = Closure::once_into_js(move |_: f64| {
                 runner.send_event(Event::WindowEvent {
                     window_id: RootWI(WindowId),
                     event: WindowEvent::RedrawRequested
                 });
-            }) as Box<Fn(f64)>).as_ref().unchecked_ref());
+            });
+            window().request_animation_frame(closure.as_ref().unchecked_ref());
         });
 
         let window = Window {