foo() {
      var constraints = {
          audio: true,
          video: true
     };

    navigator.mediaDevices
      .getUserMedia(constraints)
      .then((stream: any) => {
        let video = this.$refs as HTMLFormElement;
        video.srcObject = stream;
        video.srcObject.getTracks().forEach((element: any) => {
          element.stop();
        });
      })
      .catch((error: any) => {
        console.log("navigator.getUserMedia error: ", error);
      });
  }