How to use the ngx-webcam.WebcamUtil.getAvailableVideoInputs function in ngx-webcam

ngOnInit() {
    WebcamUtil.getAvailableVideoInputs()
      .then((mediaDevices: MediaDeviceInfo[]) => {
        this.multipleWebcamsAvailable = mediaDevices && mediaDevices.length > 1;
      });

    // Use enter key to get the current snapshot
    // tslint:disable-next-line:only-arrow-functions
    document.body.addEventListener('keypress', function(event) {
      if (event.keyCode === 13) {
          console.log('You pressed Enter key.');
          document.getElementById('buttonSnapshot').click();
      }
    });

    this.loadAudio();

    this.stageId = 1;

public ngOnInit(): void {
    WebcamUtil.getAvailableVideoInputs()
      .then((mediaDevices: MediaDeviceInfo[]) => {
        this.multipleWebcamsAvailable = mediaDevices && mediaDevices.length > 1;
      });
  }