constructor()

in packages/metro-runtime/src/modules/HMRClient.js [43:99]

• 47 lines of code
• 8 McCabe index (conditional complexity)

  constructor(url: string) {
    super();

    // Access the global WebSocket object only after enabling the client,
    // since some polyfills do the initialization lazily.
    this._ws = new global.WebSocket(url);
    this._ws.onopen = () => {
      this._state = 'open';
      this.emit('open');
      this._flushQueue();
    };
    this._ws.onerror = error => {
      this.emit('connection-error', error);
    };
    this._ws.onclose = () => {
      this._state = 'closed';
      this.emit('close');
    };
    this._ws.onmessage = message => {
      const data: HmrMessage = JSON.parse(String(message.data));

      switch (data.type) {
        case 'bundle-registered':
          this.emit('bundle-registered');
          break;

        case 'update-start':
          this.emit('update-start', data.body);
          break;

        case 'update':
          this.emit('update', data.body);
          break;

        case 'update-done':
          this.emit('update-done');
          break;

        case 'error':
          this.emit('error', data.body);
          break;

        default:
          this.emit('error', {type: 'unknown-message', message: data});
      }
    };

    this.on('update', (update: HmrUpdate) => {
      if (this._isEnabled) {
        injectUpdate(update);
      } else if (this._pendingUpdate == null) {
        this._pendingUpdate = update;
      } else {
        this._pendingUpdate = mergeUpdates(this._pendingUpdate, update);
      }
    });
  }