Add cancel event (#4476)

* feat: add cancel event

* feat: provide cancel event

* feat: insert cancel event in web

* fix: typo

* feat: propagate implementation of cancel event

* fix merge conflicts / tests

---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>

packages/web/src/events/cancel.rs

@@ -0,0 +1,17 @@
+use super::{Synthetic, WebEventExt};
+use dioxus_html::HasCancelData;
+
+impl HasCancelData for Synthetic<web_sys::Event> {
+    fn as_any(&self) -> &dyn std::any::Any {
+        &self.event
+    }
+}
+
+impl WebEventExt for dioxus_html::CancelData {
+    type WebEvent = web_sys::Event;
+
+    #[inline(always)]
+    fn try_as_web_event(&self) -> Option<Self::WebEvent> {
+        self.downcast::<web_sys::Event>().cloned()
+    }
+}

packages/web/src/events/mod.rs

@@ -7,6 +7,7 @@ use wasm_bindgen::JsCast;
 use web_sys::{Document, Element, Event};
 
 mod animation;
+mod cancel;
 mod clipboard;
 mod composition;
 mod drag;
@@ -60,6 +61,14 @@ impl HtmlEventConverter for WebEventConverter {
         Synthetic::<web_sys::AnimationEvent>::from(downcast_event(event).raw.clone()).into()
     }
 
+    #[inline(always)]
+    fn convert_cancel_data(
+        &self,
+        event: &dioxus_html::PlatformEventData,
+    ) -> dioxus_html::CancelData {
+        Synthetic::new(downcast_event(event).raw.clone()).into()
+    }
+
     #[inline(always)]
     fn convert_clipboard_data(
         &self,