JS: add Promise class

js/js.libraries/src/core/promise.kt

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2010-2017 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package kotlin.js
+
+public open external class Promise<out T>(executor: (resolve: (T) -> Unit, reject: (Throwable) -> Unit) -> Unit) {
+    companion object {
+        public fun <S> all(promise: Array<out Promise<S>>): Promise<Array<in S>>
+
+        public fun <S> race(promise: Array<out Promise<S>>): Promise<S>
+
+        public fun reject(e: Throwable): Promise<Nothing>
+
+        public fun <S> resolve(e: S): Promise<S>
+    }
+
+    public open fun <S> then(onFulfilled: ((T) -> S)?, onRejected: ((Throwable) -> S)? = definedExternally): Promise<S>
+
+    public open fun <S> catch(onRejected: (Throwable) -> S): Promise<S>
+}