node: fromEventEmitter

src/vs/base/node/event.ts

@@ -0,0 +1,18 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+'use strict';
+
+import Event, { Emitter }  from 'vs/base/common/event';
+import { EventEmitter } from 'events';
+
+export function fromEventEmitter<T>(emitter: EventEmitter, eventName: string, map: (...args: any[]) => T = ([arg]) => arg): Event<T> {
+	const fn = (...args) => result.fire(map(...args));
+	const onFirstListenerAdd = () => emitter.on(eventName, fn);
+	const onLastListenerRemove = () => emitter.removeListener(eventName, fn);
+	const result = new Emitter<T>({ onFirstListenerAdd, onLastListenerRemove });
+
+	return result.event;
+};