Function isFallbackCompositionEnd

code/redux/public/app.js:3491–3508

* Does our fallback mode think that this event is the end of composition? * * @param {string} topLevelType * @param {object} nativeEvent * @return {boolean}

(topLevelType, nativeEvent)

 * @return {boolean}
 */
function isFallbackCompositionEnd(topLevelType, nativeEvent) {
  switch (topLevelType) {
    case 'topKeyUp':
      // Command keys insert or clear IME input.
      return END_KEYCODES.indexOf(nativeEvent.keyCode) !== -1;
    case 'topKeyDown':
      // Expect IME keyCode on each keydown. If we get any other
      // code we must have exited earlier.
      return nativeEvent.keyCode !== START_KEYCODE;
    case 'topKeyPress':
    case 'topMouseDown':
    case 'topBlur':
      // Events are not possible without cancelling IME.
      return true;
    default:
      return false;
  }
}

/**
 * Google Input Tools provides composition data via a CustomEvent,