Stop/Close webcam stream which is opened by navigator.mediaDevices.getUserMedia

Don't use stream.stop(), it's deprecated

MediaStream Deprecations

Use stream.getTracks().forEach(track => track.stop())

Suppose we have streaming in video tag and id is video - <video id="video"></video> then we should have following code -

var videoEl = document.getElementById('video');
// now get the steam 
stream = videoEl.srcObject;
// now get all tracks
tracks = stream.getTracks();
// now close each track by having forEach loop
tracks.forEach(function(track) {
   // stopping every track
   track.stop();
});
// assign null to srcObject of video
videoEl.srcObject = null;

You need to stop all tracks (from webcam, microphone):

localStream.getTracks().forEach(track => track.stop());

Start and Stop Web Camera,(Update 2020 React es6 )

Start Web Camera

stopWebCamera =()=>

       //Start Web Came
      if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
        //use WebCam
        navigator.mediaDevices.getUserMedia({ video: true }).then(stream => {
          this.localStream = stream;
          this.video.srcObject = stream;
          this.video.play();
        });
      }
 }

Stop Web Camera or Video playback in general

stopVideo =()=>
{
        this.video.pause();
        this.video.src = "";
        this.video.srcObject = null;

         // As per new API stop all streams
        if (this.localStream)
          this.localStream.getTracks().forEach(track => track.stop());
}

Stop Web Camera function works even with video streams:

  this.video.src = this.state.videoToTest;
  this.video.play();

Please check this: https://jsfiddle.net/wazb1jks/3/

navigator.getUserMedia(mediaConstraints, function(stream) {
    window.streamReference = stream;
}, onMediaError);

Stop Recording

function stopStream() {
    if (!window.streamReference) return;

    window.streamReference.getAudioTracks().forEach(function(track) {
        track.stop();
    });

    window.streamReference.getVideoTracks().forEach(function(track) {
        track.stop();
    });

    window.streamReference = null;
}

The following code worked for me:

public vidOff() {

      let stream = this.video.nativeElement.srcObject;
      let tracks = stream.getTracks();

      tracks.forEach(function (track) {
          track.stop();
      });

      this.video.nativeElement.srcObject = null;
      this.video.nativeElement.stop();
  }