fix(youtube-player): errors during server-side rendering

Fixes the `youtube-player` component throwing errors if it's rendered on the server. Also does some minor code cleanup.

Author: crisbeto

src/universal-app/BUILD.bazel

@@ -18,6 +18,7 @@ ng_module(
     ],
     deps = [
         "@npm//@angular/platform-server",
+        "//src/youtube-player",
     ] + CDK_TARGETS + CDK_EXPERIMENTAL_TARGETS + MATERIAL_TARGETS + MATERIAL_EXPERIMENTAL_TARGETS,
 )
 

src/universal-app/kitchen-sink/kitchen-sink.html

@@ -379,3 +379,7 @@ <h2>Virtual scroll</h2>
     Item #{{i}}
   </div>
 </cdk-virtual-scroll-viewport>
+
+<h2>YouTube player</h2>
+
+<youtube-player videoId="dQw4w9WgXcQ"></youtube-player>

src/universal-app/kitchen-sink/kitchen-sink.ts

@@ -37,6 +37,7 @@ import {MatDividerModule} from '@angular/material/divider';
 import {MatFormFieldModule} from '@angular/material/form-field';
 import {MatSortModule} from '@angular/material/sort';
 import {MatStepperModule} from '@angular/material/stepper';
+import {YouTubePlayerModule} from '@angular/youtube-player';
 import {Observable, of as observableOf} from 'rxjs';
 
 export class TableDataSource extends DataSource<any> {
@@ -136,6 +137,9 @@ export class KitchenSink {
     // CDK Modules
     CdkTableModule,
     DragDropModule,
+
+    // Other modules
+    YouTubePlayerModule,
   ],
   declarations: [KitchenSink, TestEntryComponent],
   exports: [KitchenSink, TestEntryComponent],

src/youtube-player/BUILD.bazel

@@ -20,7 +20,6 @@ ng_module(
     ),
     module_name = "@angular/youtube-player",
     deps = [
-        "@npm//@angular/common",
         "@npm//@angular/core",
         "@npm//@types/youtube",
         "@npm//rxjs",

src/youtube-player/youtube-module.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {CommonModule} from '@angular/common';
 import {NgModule} from '@angular/core';
 
 import {YouTubePlayer} from './youtube-player';
@@ -16,7 +15,6 @@ const COMPONENTS = [YouTubePlayer];
 @NgModule({
   declarations: COMPONENTS,
   exports: COMPONENTS,
-  imports: [CommonModule],
 })
 export class YouTubePlayerModule {
 }

src/youtube-player/youtube-player.ts

@@ -69,6 +69,9 @@ interface Player extends YT.Player {
 // The only field available is destroy and addEventListener.
 type UninitializedPlayer = Pick<Player, 'videoId' | 'destroy' | 'addEventListener'>;
 
+/** Whether we're currently rendering inside a browser. */
+const isBrowser = typeof window === 'object' && !!window;
+
 /**
  * Angular component that renders a YouTube player via the YouTube player
  * iframe API.
@@ -80,7 +83,7 @@ type UninitializedPlayer = Pick<Player, 'videoId' | 'destroy' | 'addEventListene
   changeDetection: ChangeDetectionStrategy.OnPush,
   encapsulation: ViewEncapsulation.None,
   // This div is *replaced* by the YouTube player embed.
-  template: '<div #youtube_container></div>',
+  template: '<div #youtubeContainer></div>',
 })
 export class YouTubePlayer implements AfterViewInit, OnDestroy, OnInit {
   /** YouTube Video ID to view */
@@ -147,15 +150,21 @@ export class YouTubePlayer implements AfterViewInit, OnDestroy, OnInit {
   @Output() playbackRateChange = new EventEmitter<YT.OnPlaybackRateChangeEvent>();
 
   /** The element that will be replaced by the iframe. */
-  @ViewChild('youtube_container', {static: false}) youtubeContainer: ElementRef | undefined;
+  @ViewChild('youtubeContainer', {static: false})
+  youtubeContainer: ElementRef<HTMLElement>;
+
   private _youtubeContainer = new EventEmitter<HTMLElement>();
   private _destroyed = new EventEmitter<undefined>();
-
   private _player: Player | undefined;
 
   constructor(private _ngZone: NgZone) {}
 
   ngOnInit() {
+    // Don't do anything if we're not in a browser environment.
+    if (!isBrowser) {
+      return;
+    }
+
     let iframeApiAvailableObs: Observable<boolean> = observableOf(true);
     if (!window.YT) {
       if (this.showBeforeIframeApiLoads) {
@@ -223,19 +232,15 @@ export class YouTubePlayer implements AfterViewInit, OnDestroy, OnInit {
   }
 
   ngAfterViewInit() {
-    if (!this.youtubeContainer) {
-      return;
-    }
     this._youtubeContainer.emit(this.youtubeContainer.nativeElement);
   }
 
   ngOnDestroy() {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.destroy();
+      window.onYouTubeIframeAPIReady = undefined;
+      this._destroyed.emit();
     }
-    this._player.destroy();
-    window.onYouTubeIframeAPIReady = undefined;
-    this._destroyed.emit();
   }
 
   private _runInZone<T extends (...args: any[]) => void>(callback: T):
@@ -249,166 +254,122 @@ export class YouTubePlayer implements AfterViewInit, OnDestroy, OnInit {
 
   /** See https://developers.google.com/youtube/iframe_api_reference#playVideo */
   playVideo() {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.playVideo();
     }
-    this._player.playVideo();
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#pauseVideo */
   pauseVideo() {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.pauseVideo();
     }
-    this._player.pauseVideo();
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#stopVideo */
   stopVideo() {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.stopVideo();
     }
-    this._player.stopVideo();
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#seekTo */
   seekTo(seconds: number, allowSeekAhead: boolean) {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.seekTo(seconds, allowSeekAhead);
     }
-    this._player.seekTo(seconds, allowSeekAhead);
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#mute */
   mute() {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.mute();
     }
-    this._player.mute();
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#unMute */
   unMute() {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.unMute();
     }
-    this._player.unMute();
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#isMuted */
   isMuted(): boolean {
-    if (!this._player) {
-      return false;
-    }
-    return this._player.isMuted();
+    return !this._player || this._player.isMuted();
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#setVolume */
   setVolume(volume: number) {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      this._player.setVolume(volume);
     }
-    this._player.setVolume(volume);
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getVolume */
   getVolume(): number {
-    if (!this._player) {
-      return 0;
-    }
-    return this._player.getVolume();
+    return this._player ? this._player.getVolume() : 0;
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#setPlaybackRate */
   setPlaybackRate(playbackRate: number) {
-    if (!this._player) {
-      return;
+    if (this._player) {
+      return this._player.setPlaybackRate(playbackRate);
     }
-    return this._player.setPlaybackRate(playbackRate);
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getPlaybackRate */
   getPlaybackRate(): number {
-    if (!this._player) {
-      return 0;
-    }
-    return this._player.getPlaybackRate();
+    return this._player ? this._player.getPlaybackRate() : 0;
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getAvailablePlaybackRates */
   getAvailablePlaybackRates(): number[] {
-    if (!this._player) {
-      return [];
-    }
-    return this._player.getAvailablePlaybackRates();
+    return this._player ? this._player.getAvailablePlaybackRates() : [];
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getVideoLoadedFraction */
   getVideoLoadedFraction(): number {
-    if (!this._player) {
-      return 0;
-    }
-    return this._player.getVideoLoadedFraction();
+    return this._player ? this._player.getVideoLoadedFraction() : 0;
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getPlayerState */
   getPlayerState(): YT.PlayerState | undefined {
-    if (!window.YT) {
+    if (isBrowser && !window.YT) {
       return undefined;
     }
 
-    if (!this._player) {
-      return YT.PlayerState.UNSTARTED;
-    }
-    return this._player.getPlayerState();
+    return this._player ? this._player.getPlayerState() : YT.PlayerState.UNSTARTED;
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getCurrentTime */
   getCurrentTime(): number {
-    if (!this._player) {
-      return 0;
-    }
-    return this._player.getCurrentTime();
+    return this._player ? this._player.getCurrentTime() : 0;
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getPlaybackQuality */
   getPlaybackQuality(): YT.SuggestedVideoQuality {
-    if (!this._player) {
-      return 'default';
-    }
-    return this._player.getPlaybackQuality();
+    return this._player ? this._player.getPlaybackQuality() : 'default';
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getAvailableQualityLevels */
   getAvailableQualityLevels(): YT.SuggestedVideoQuality[] {
-    if (!this._player) {
-      return [];
-    }
-    return this._player.getAvailableQualityLevels();
+    return this._player ? this._player.getAvailableQualityLevels() : [];
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getDuration */
   getDuration(): number {
-    if (!this._player) {
-      return 0;
-    }
-    return this._player.getDuration();
+    return this._player ? this._player.getDuration() : 0;
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getVideoUrl */
   getVideoUrl(): string {
-    if (!this._player) {
-      return '';
-    }
-    return this._player.getVideoUrl();
+    return this._player ? this._player.getVideoUrl() : '';
   }
 
   /** See https://developers.google.com/youtube/iframe_api_reference#getVideoEmbedCode */
   getVideoEmbedCode(): string {
-    if (!this._player) {
-      return '';
-    }
-    return this._player.getVideoEmbedCode();
+    return this._player ? this._player.getVideoEmbedCode() : '';
   }
 }