feat(extends): extend promise

crates/js-sys/src/lib.rs

@@ -3783,6 +3783,7 @@ extern {
     /// an asynchronous operation, and its resulting value.
     ///
     /// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise
+    #[wasm_bindgen(extends = Object)]
     pub type Promise;
 
     /// Creates a new `Promise` with the provided executor `cb`

crates/js-sys/tests/wasm/Promise.rs

@@ -0,0 +1,11 @@
+use wasm_bindgen_test::*;
+use wasm_bindgen::JsCast;
+use js_sys::*;
+
+#[wasm_bindgen_test]
+fn promise_inheritance() {
+    let promise = Promise::new(&mut |_, _| ());
+    assert!(promise.is_instance_of::<Promise>());
+    assert!(promise.is_instance_of::<Object>());
+    let _: &Object = promise.as_ref();
+}

crates/js-sys/tests/wasm/main.rs

@@ -26,6 +26,7 @@ pub mod MapIterator;
 pub mod Math;
 pub mod Number;
 pub mod Object;
+pub mod Promise;
 pub mod Proxy;
 pub mod RangeError;
 pub mod ReferenceError;