Add Promise.allSettled and AllSettledResultElement

java/elemental2/promise/AllSettledResultElement.java

@@ -0,0 +1,20 @@
+package elemental2.promise;
+
+import jsinterop.annotations.JsProperty;
+import jsinterop.annotations.JsType;
+
+/**
+ * Represents an element of the array returned by Promise.allSettled().
+ * @param <VALUE> the type of the succeeded promise.
+ */
+@JsType(isNative = true)
+public interface AllSettledResultElement<VALUE> {
+    @JsProperty
+    String getStatus();
+
+    @JsProperty
+    VALUE getValue();
+
+    @JsProperty
+    Object getReason();
+}

java/elemental2/promise/Promise.java

@@ -124,6 +124,16 @@ public interface ResolveValueUnionType<V extends @Nullable Object> {
   private static native <V extends @Nullable Object> Promise<V> raceInternal(
       IThenable<? extends V>[] promises);
 
+  @JsOverlay
+  public static <V extends @Nullable Object> Promise<AllSettledResultElement<V>[]> allSettled(
+      IThenable<? extends V>... promises) {
+    return allSettledInternal(promises);
+  }
+
+  @JsMethod(name = "allSettled")
+  private static native <V extends @Nullable Object> Promise<AllSettledResultElement<V>[]> allSettledInternal(
+      IThenable<? extends V>[] promises);
+
   public static native <V extends @Nullable Object> Promise<V> reject(@Nullable Object error);
 
   @JsOverlay

java/elemental2/promise/promise.types

@@ -1,2 +1,3 @@
 IThenable=elemental2.promise.IThenable
-Promise=elemental2.promise.Promise
+Promise=elemental2.promise.Promise
+AllSettledResultElement=elemental2.promise.AllSettledResultElement