function getCompositionEventType(domEventName) {
    switch (domEventName) {
      case 'compositionstart':
        return 'onCompositionStart';

      case 'compositionend':
        return 'onCompositionEnd';

      case 'compositionupdate':
        return 'onCompositionUpdate';
    }
  }
Translate native top level events into event types.