better resilience on notifications and empty polls

src/app/components/stream/status/poll/poll.component.html

@@ -1,4 +1,4 @@
-<div class="poll">
+<div class="poll" *ngIf="poll">
     <div *ngIf="!poll.voted && !poll.expired">
         <div *ngFor="let o of options">
             <label class="poll__container">

src/app/components/stream/status/poll/poll.component.ts

@@ -30,6 +30,8 @@ export class PollComponent implements OnInit {
     private _poll: Poll;
     @Input('poll')
     set poll(value: Poll) {
+        if(!value) return;
+
         this._poll = value;
 
         this.pollName = this.poll.id;

src/app/services/streaming.service.ts

@@ -45,7 +45,11 @@ export class StreamingWrapper {
 
     private start(route: string) {
         this.eventSource = new WebSocket(route);
-        this.eventSource.onmessage = x => this.statusParsing(<WebSocketEvent>JSON.parse(x.data));
+        this.eventSource.onmessage = x => {
+            if (x.data !== '') {
+                this.statusParsing(<WebSocketEvent>JSON.parse(x.data));
+            }
+        }
         this.eventSource.onerror = x => this.webSocketGotError(x);
         this.eventSource.onopen = x => { };
         this.eventSource.onclose = x => this.webSocketClosed(route, x);