add dispatch_custom_event to enable dispatching CustomEvent's

crates/web-sys/src/features/gen_EventTarget.rs

@@ -156,6 +156,14 @@ extern "C" {
     #[doc = ""]
     #[doc = "*This API requires the following crate features to be activated: `Event`, `EventTarget`*"]
     pub fn dispatch_event(this: &EventTarget, event: &Event) -> Result<bool, JsValue>;
+    #[cfg(feature = "CustomEvent")]
+    # [wasm_bindgen (catch , method , structural , js_class = "EventTarget" , js_name = dispatchEvent)]
+    #[doc = "The `dispatchEvent()` method."]
+    #[doc = ""]
+    #[doc = "[MDN Documentation](https://developer.mozilla.org/en-US/docs/Web/API/EventTarget/dispatchEvent)"]
+    #[doc = ""]
+    #[doc = "*This API requires the following crate features to be activated: `CustomEvent`, `EventTarget`*"]
+    pub fn dispatch_custom_event(this: &EventTarget, event: &CustomEvent) -> Result<bool, JsValue>;
     # [wasm_bindgen (catch , method , structural , js_class = "EventTarget" , js_name = removeEventListener)]
     #[doc = "The `removeEventListener()` method."]
     #[doc = ""]

crates/web-sys/tests/wasm/custom_event.js

@@ -0,0 +1,11 @@
+export function new_custom_event() {
+  return new Promise(resolve => {
+    window.addEventListener("test-custom-event", resolve);
+    window.dispatchEvent(new CustomEvent("test-custom-event", {
+      detail: "detail",
+      bubbles: true,
+      cancelable: true,
+      composed: true,
+    }));
+  });
+}

crates/web-sys/tests/wasm/custom_event.rs

@@ -0,0 +1,31 @@
+use js_sys::{Object, Promise};
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_futures::JsFuture;
+use wasm_bindgen_test::*;
+use web_sys::CustomEvent;
+
+#[wasm_bindgen(module = "/tests/wasm/custom_event.js")]
+extern "C" {
+    fn new_custom_event() -> Promise;
+}
+
+#[wasm_bindgen_test]
+async fn custom_event() {
+    let result = JsFuture::from(new_custom_event()).await.unwrap();
+    let event = CustomEvent::from(result);
+    // All DOM interfaces should inherit from `Object`.
+    assert!(event.is_instance_of::<Object>());
+    let _: &Object = event.as_ref();
+
+    // These should match `new Event`.
+    assert!(event.bubbles());
+    assert!(event.cancelable());
+    assert!(event.composed());
+    assert_eq!(event.detail().as_string().unwrap(), "detail");
+
+    // The default behavior not initially prevented, but after
+    // we call `prevent_default` it better be.
+    assert!(!event.default_prevented());
+    event.prevent_default();
+    assert!(event.default_prevented());
+}