event: fromPromise, stopwatch

src/vs/base/common/event.ts

@@ -152,7 +152,25 @@ export function fromEventEmitter<T>(emitter: EventEmitter, eventType: string): E
 	};
 }
 
-export function fromPromise<T>(promise: TPromise<Event<T>>): Event<T> {
+export function fromPromise(promise: TPromise<any>): Event<void> {
+	const emitter = new Emitter<void>();
+	let shouldEmit = false;
+
+	promise
+		.then(null, () => null)
+		.then(() => {
+			if (!shouldEmit) {
+				setTimeout(() => emitter.fire(), 0);
+			} else {
+				emitter.fire();
+			}
+		});
+
+	shouldEmit = true;
+	return emitter.event;
+}
+
+export function delayed<T>(promise: TPromise<Event<T>>): Event<T> {
 	let toCancel: TPromise<any> = null;
 	let listener: IDisposable = null;
 
@@ -275,3 +293,8 @@ export class EventBufferer {
 		buffer.forEach(flush => flush());
 	}
 }
+
+export function stopwatch<T>(event: Event<T>): Event<number> {
+	const start = new Date().getTime();
+	return mapEvent(once(event), _ => new Date().getTime() - start);
+}
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src/vs/base/test/common/event.test.ts

@@ -5,10 +5,11 @@
 'use strict';
 
 import * as assert from 'assert';
-import Event, {Emitter, fromEventEmitter, debounceEvent, EventBufferer, once} from 'vs/base/common/event';
+import Event, {Emitter, fromEventEmitter, debounceEvent, EventBufferer, once, fromPromise, stopwatch} from 'vs/base/common/event';
 import {IDisposable} from 'vs/base/common/lifecycle';
 import {EventEmitter} from 'vs/base/common/eventEmitter';
 import Errors = require('vs/base/common/errors');
+import {TPromise} from 'vs/base/common/winjs.base';
 
 namespace Samples {
 
@@ -282,4 +283,67 @@ suite('EventBufferer', () => {
 		listener1.dispose();
 		listener2.dispose();
 	});
+});
+
+suite('fromPromise', () => {
+
+	test('should emit when done', () => {
+		let count = 0;
+
+		const event = fromPromise(TPromise.as(null));
+		event(() => count++);
+
+		assert.equal(count, 0);
+
+		return TPromise.timeout(10).then(() => {
+			assert.equal(count, 1);
+		});
+	});
+
+	test('should emit when done - setTimeout', () => {
+		let count = 0;
+
+		const event = fromPromise(TPromise.timeout(5));
+		event(() => count++);
+
+		assert.equal(count, 0);
+
+		return TPromise.timeout(10).then(() => {
+			assert.equal(count, 1);
+		});
+	});
+
+	test('should emit when done - setTimeout', () => {
+		let count = 0;
+
+		const event = fromPromise(TPromise.timeout(10));
+		event(() => count++);
+
+		assert.equal(count, 0);
+
+		return TPromise.timeout(0).then(() => {
+			assert.equal(count, 0);
+
+			return TPromise.timeout(10).then(() => {
+				assert.equal(count, 1);
+			});
+		});
+	});
+});
+
+suite('stopwatch', () => {
+
+	test('should emit when done', () => {
+		const emitter = new Emitter<void>();
+		const event = stopwatch(emitter.event);
+
+		return new TPromise(c => {
+			event(duration => {
+				assert(duration > 5);
+				c(null);
+			});
+
+			setTimeout(() => emitter.fire(), 5);
+		});
+	});
 });
\ No newline at end of file