离子测试幻灯片，无法读取 initEvents 未定义的属性“订阅”答案

【问题标题】：Ionic testing Slides, Cannot read property 'subscribe' of undefined at initEvents离子测试幻灯片，无法读取 initEvents 未定义的属性“订阅”
【发布时间】：2017-04-26 22:56:29
【问题描述】：

使用 Ionic 3，使用 ion-slides，您可能会遇到以下错误：

Failed: Cannot read property 'subscribe' of undefined
    TypeError: Cannot read property 'subscribe' of undefined
        at initEvents (http://localhost:9877webpack:///~/ionic-angular/components/slides/swiper/swiper-events.js:63:0 <- src/test.ts:128385:48)
        at Slides._initSlides (http://localhost:9877webpack:///~/ionic-angular/components/slides/slides.js:815:0 <- src/test.ts:61766:127)
        at SafeSubscriber._next (http://localhost:9877webpack:///~/ionic-angular/components/slides/slides.js:530:0 <- src/test.ts:61481:23)
        at SafeSubscriber.__tryOrUnsub (http://localhost:9877webpack:///~/rxjs/Subscriber.js:234:0 <- src/test.ts:17652:16)
        at SafeSubscriber.next (http://localhost:9877webpack:///~/rxjs/Subscriber.js:183:0 <- src/test.ts:17601:22)
        at Subscriber._next (http://localhost:9877webpack:///~/rxjs/Subscriber.js:125:0 <- src/test.ts:17543:26)
        at Subscriber.next (http://localhost:9877webpack:///~/rxjs/Subscriber.js:89:0 <- src/test.ts:17507:18)
        at http://localhost:9877webpack:///~/rxjs/observable/PromiseObservable.js:66:0 <- src/test.ts:115833:36
        at ZoneDelegate.invoke (http://localhost:9877webpack:///~/zone.js/dist/zone.js:365:0 <- src/polyfills.ts:1520:26)
        at AsyncTestZoneSpec.onInvoke (http://localhost:9877webpack:///~/zone.js/dist/async-test.js:49:0 <- src/test.ts:118535:39)
        at ProxyZoneSpec.onInvoke (http://localhost:9877webpack:///~/zone.js/dist/proxy.js:76:0 <- src/test.ts:119221:39)
        at ZoneDelegate.invoke (http://localhost:9877webpack:///~/zone.js/dist/zone.js:364:0 <- src/polyfills.ts:1519:32)
        at Object.onInvoke (http://localhost:9877webpack:///~/@angular/core/@angular/core.es5.js:4145:0 <- src/test.ts:6663:37)
        at ZoneDelegate.invoke (http://localhost:9877webpack:///~/zone.js/dist/zone.js:364:0 <- src/polyfills.ts:1519:32)
        at Zone.run (http://localhost:9877webpack:///~/zone.js/dist/zone.js:125:0 <- src/polyfills.ts:1280:43)

此错误是由订阅 platform.resize 的行引起的，在 ionic repo 上可以看到：https://github.com/driftyco/ionic/blob/e1913211930a53e77a4d18b70f673fea9799be75/src/components/slides/swiper/swiper-events.ts#L87

【问题讨论】：

标签： ionic-framework ionic2

【解决方案1】：

您需要做的是将此添加到您的 Platform mock，这样 Observable 就不会将 subscribe 添加到您的模拟中未定义的内容中。

  get resize(): Observable<any> {
    return Observable.of(true);
  }

这也是我完整的 Platform Mock，以防万一有人需要。

import { Observable } from 'rxjs/Observable'

export class PlatformMock {
  public ready(): Promise<{String}> {
    return new Promise((resolve) => {
      resolve('READY');
    });
  }

  public registerBackButtonAction(fn: Function, priority?: number): Function {
    return (() => true);
  }

  public hasFocus(ele: HTMLElement): boolean {
    return true;
  }

  public doc(): HTMLDocument {
    return document;
  }

  public is(): boolean {
    return true;
  }

  public getElementComputedStyle(container: any): any {
    return {
      paddingLeft: '10',
      paddingTop: '10',
      paddingRight: '10',
      paddingBottom: '10',
    };
  }

  public onResize(callback: any) {
    return callback;
  }

  get resize(): Observable<any> {
    return Observable.of(true);
  }

  public registerListener(ele: any, eventName: string, callback: any): Function {
    return (() => true);
  }

  public win(): Window {
    return window;
  }

  public raf(callback: any): number {
    return 1;
  }

  public timeout(callback: any, timer: number): any {
    return setTimeout(callback, timer);
  }

  public cancelTimeout(id: any) {
    // do nothing
  }

  public getActiveElement(): any {
    return document['activeElement'];
  }

}

【讨论】：