fix: translate more

fix: a NPE

aio/src/app/embedded/live-example/live-example.component.html

@@ -1,12 +1,12 @@
 <span [ngSwitch]="mode">
-  <span *ngSwitchCase="'disabled'">{{title}} <em>(not available on this device)</em></span>
+  <span *ngSwitchCase="'disabled'">{{title}} <em>(在此设备上不可用)</em></span>
   <span *ngSwitchCase="'embedded'">
     <div *ngIf="showEmbedded" title="{{title}}">
       <aio-embedded-plunker [src]="plnkr"></aio-embedded-plunker>
     </div>
     <img *ngIf="!showEmbedded" (click)="toggleEmbedded()" [src]="plnkrImg" alt="{{title}}">
     <p *ngIf="enableDownload">
-      You can also <a [href]="zip" download title="Download example">download this example</a>.
+      你还可以 <a [href]="zip" download title="下载范例">下载这个例子</a>。
     </p>
   </span>
   <span *ngSwitchCase="'downloadOnly'">
@@ -15,7 +15,7 @@
   <span *ngSwitchDefault>
     <a [href]="plnkr" target="_blank" title="{{title}}">{{title}}</a>
     <span *ngIf="enableDownload">
-      /  <a [href]="zip" download title="Download example">download example</a>
+      /  <a [href]="zip" download title="下载范例">下载范例</a>
     </span>
   </span>
 </span>

aio/src/app/embedded/live-example/live-example.component.ts

@@ -145,7 +145,7 @@ export class LiveExampleComponent implements OnInit {
     // It is the original innerHTML of the host element.
     // Angular will sanitize this title when displayed so should be plain text.
     const title = this.elementRef.nativeElement.liveExampleContent;
-    this.title = (title || this.attrs.title || 'live example').trim();
+    this.title = (title || this.attrs.title || '在线例子').trim();
     this.onResize(window.innerWidth);
   }
 

aio/src/app/shared/toc.service.ts

@@ -76,7 +76,7 @@ export class TocService {
   private isOriginalText(heading: HTMLHeadingElement): boolean {
     if (heading && heading.hasAttribute('translation-origin')) {
       const prevNode = heading.previousElementSibling;
-      if (prevNode.hasAttribute('translation-result')) {
+      if (prevNode && prevNode.hasAttribute('translation-result')) {
         return true;
       }
     }