docs: function normalizeNativeEvent(nativeEvent: Object) {
    if (!nativeEvent || nativeEvent._normalized) {
      return nativeEvent;
    }
    const eventType = nativeEvent.type || '';
    const mouse = eventType.indexOf('mouse') >= 0;
    if (mouse) {
      return normalizeMouseEvent(nativeEvent);
    } else {
      return normalizeTouchEvent(nativeEvent);
    }
  }