Useful for creating user media streams and tearing them back down.

user_media_stream_manager.js

// StreamManager
//   Useful for creating user media streams and tearing them back down.
//
class StreamManager {
  constructor() {
    this._stream = null;
    this._constraints = null;
  }

  get stream() {
    return this._stream;
  }

  set stream() {
    throw(Error("StreamManager error: stream may not be set by the user, please call `create`."));
  }

  get constraints() {
    return this._constraints;
  }

  set constraints() {
    throw(Error("StreamManager error: constraints may not be set by the user, please pass constraints when calling `create`."));
  }

  create(constraints) {
    return new Promise((resolve, reject) => {
      if (this._stream) {
        this.teardown();
      }

      navigator.mediaDevices.getUserMedia(constraints)
        .then(stream => {
          this._stream = stream;
          this._constraints = constraints;

          resolve(this._stream);
        })
        .catch(reject);
    });
  }

  teardown() {
    this._stream.getTracks().forEach(track => track.stop());
    this._stream = null;
    this._constraints = null;
  }
}

export default StreamManager;