Angular - 如何从navigator.getUserMedia设置视频src？

Question

我正在尝试为Angular中的视频元素设置网络摄像头流。

    import {Component, View, bootstrap} from "angular2/angular2";

    @Component({
        selector: "home",
    })
    @View({
        template:`<video [src]="videosrc"></video>`
    })
    export default class Home {

        videosrc: string;
        constructor(){

            //setTimeout(() => {}, 2000);

            navigator.getUserMedia = navigator.getUserMedia || navigator.mozGetUserMedia || navigator.webkitGetUserMedia;
            navigator.getUserMedia({video: true},(stream) => {
                this.videosrc= URL.createObjectURL(stream);
            }, (err) => console.log(err));  
        }
    }

仅在添加＆＃34; setTimeout（（）=＆gt; {}，2000）之后才能工作;＆＃34;。

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