Function isFallbackCompositionStart

code/event-handlers/public/app.js:2559–2561

* Does our fallback best-guess model think this event signifies that * composition has begun? * * @param {string} topLevelType * @param {object} nativeEvent * @return {boolean}

(topLevelType, nativeEvent)

 * @return {boolean}
 */
function isFallbackCompositionStart(topLevelType, nativeEvent) {
  return topLevelType === 'topKeyDown' && nativeEvent.keyCode === START_KEYCODE;
}

/**
 * Does our fallback mode think that this event is the end of composition?