feat(PromisePipe): add pipe for promises
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import {Promise, PromiseWrapper} from 'angular2/src/facade/async';
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import {isBlank, isPresent} from 'angular2/src/facade/lang';
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import {Pipe, WrappedValue} from './pipe';
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import {ChangeDetectorRef} from '../change_detector_ref';
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// HACK: workaround for Traceur behavior.
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// It expects all transpiled modules to contain this marker.
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// TODO: remove this when we no longer use traceur
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export var __esModule = true;
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/**
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* Implements async bindings to Promise.
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*
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* # Example
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*
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* In this example we bind the description promise to the DOM.
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* The async pipe will convert a promise to the value with which it is resolved. It will also
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* request a change detection check when the promise is resolved.
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*
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* ```
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* @Component({
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* selector: "task-cmp",
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* changeDetection: ON_PUSH
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* })
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* @View({
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* inline: "Task Description {{description|promise}}"
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* })
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* class Task {
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* description:Promise<string>;
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* }
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*
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* ```
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*
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* @exportedAs angular2/pipes
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*/
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export class PromisePipe extends Pipe {
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_ref: ChangeDetectorRef;
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_latestValue: Object;
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_latestReturnedValue: Object;
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_sourcePromise: Promise<any>;
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constructor(ref: ChangeDetectorRef) {
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super();
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this._ref = ref;
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this._latestValue = null;
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this._latestReturnedValue = null;
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}
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supports(promise): boolean { return PromiseWrapper.isPromise(promise); }
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onDestroy(): void {
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// NO-OP
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}
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transform(promise: Promise<any>): any {
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var pipe = this;
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if (isBlank(this._sourcePromise)) {
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this._sourcePromise = promise;
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promise.then((val) => {
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if (pipe._sourcePromise === promise) {
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pipe._updateLatestValue(val);
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}
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});
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return null;
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}
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if (promise !== this._sourcePromise) {
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this._sourcePromise = null;
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return this.transform(promise);
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}
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if (this._latestValue === this._latestReturnedValue) {
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return this._latestReturnedValue;
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} else {
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this._latestReturnedValue = this._latestValue;
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return WrappedValue.wrap(this._latestValue);
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}
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}
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_updateLatestValue(value: Object) {
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this._latestValue = value;
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this._ref.requestCheck();
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}
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}
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/**
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* Provides a factory for [PromisePipe].
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*
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* @exportedAs angular2/pipes
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*/
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export class PromisePipeFactory {
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supports(promise): boolean { return PromiseWrapper.isPromise(promise); }
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create(cdRef): Pipe { return new PromisePipe(cdRef); }
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}
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import {ddescribe, describe, it, iit, xit, expect, beforeEach, afterEach,
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AsyncTestCompleter, inject, proxy, SpyObject} from 'angular2/test_lib';
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import {IMPLEMENTS} from 'angular2/src/facade/lang';
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import {PromisePipe} from 'angular2/src/change_detection/pipes/promise_pipe';
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import {WrappedValue} from 'angular2/src/change_detection/pipes/pipe';
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import {ChangeDetectorRef} from 'angular2/src/change_detection/change_detector_ref';
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import {PromiseWrapper} from 'angular2/src/facade/async';
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export function main() {
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describe("PromisePipe", () => {
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var message = new Object();
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var pipe;
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var completer;
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var ref;
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beforeEach(() => {
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completer = PromiseWrapper.completer();
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ref = new SpyChangeDetectorRef();
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pipe = new PromisePipe(ref);
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});
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describe("supports", () => {
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it("should support promises", () => {
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expect(pipe.supports(completer.promise)).toBe(true);
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});
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it("should not support other objects", () => {
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expect(pipe.supports("string")).toBe(false);
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expect(pipe.supports(null)).toBe(false);
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});
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});
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describe("transform", () => {
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it("should return null when subscribing to a promise", () => {
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expect(pipe.transform(completer.promise)).toBe(null);
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});
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it("should return the latest available value", inject([AsyncTestCompleter], (async) => {
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pipe.transform(completer.promise);
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completer.resolve(message);
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PromiseWrapper.setTimeout(() => {
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expect(pipe.transform(completer.promise)).toEqual(new WrappedValue(message));
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async.done();
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}, 0)
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}));
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it("should return unwrapped value when nothing has changed since the last call",
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inject([AsyncTestCompleter], (async) => {
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pipe.transform(completer.promise);
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completer.resolve(message);
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PromiseWrapper.setTimeout(() => {
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pipe.transform(completer.promise);
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expect(pipe.transform(completer.promise)).toBe(message);
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async.done();
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}, 0)
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}));
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it("should dispose of the existing subscription when subscribing to a new promise",
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inject([AsyncTestCompleter], (async) => {
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pipe.transform(completer.promise);
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var newCompleter = PromiseWrapper.completer();
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expect(pipe.transform(newCompleter.promise)).toBe(null);
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// this should not affect the pipe, so it should return WrappedValue
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completer.resolve(message);
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PromiseWrapper.setTimeout(() => {
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expect(pipe.transform(newCompleter.promise)).toBe(null);
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async.done();
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}, 0)
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}));
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it("should request a change detection check upon receiving a new value",
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inject([AsyncTestCompleter], (async) => {
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pipe.transform(completer.promise);
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completer.resolve(message);
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PromiseWrapper.setTimeout(() => {
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expect(ref.spy('requestCheck')).toHaveBeenCalled();
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async.done();
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}, 0)
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}));
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});
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});
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}
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@proxy
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@IMPLEMENTS(ChangeDetectorRef)
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class SpyChangeDetectorRef extends SpyObject {
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constructor(){super(ChangeDetectorRef);}
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noSuchMethod(m){return super.noSuchMethod(m)}
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}
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