initiate a webcam and turn it into an observable.

initiate-webcam.ts

import { timer, Subject, from, Observable } from 'rxjs';

export function createWebcam(webcam: HTMLVideoElement): Observable<{}> {
  return from(
    new Promise<{}>((resolve, reject) => {
      if (navigator.getUserMedia) {
        navigator.getUserMedia(
          { video: true },
          stream => {
            webcam.srcObject = stream;
            resolve();
          },
          error => {
            reject(error);
          }
        );
      } else {
        reject(new Error('No getuserMedia method found in navigation found.'));
      }
    })
  );
}