Function isKeypressCommand

code/composition/public/app.js:3336–3340

* Return whether a native keypress event is assumed to be a command. * This is required because Firefox fires `keypress` events for key commands * (cut, copy, select-all, etc.) even though no character is inserted.

(nativeEvent)

 * (cut, copy, select-all, etc.) even though no character is inserted.
 */
function isKeypressCommand(nativeEvent) {
  return (nativeEvent.ctrlKey || nativeEvent.altKey || nativeEvent.metaKey) &&
  // ctrlKey && altKey is equivalent to AltGr, and is not a command.
  !(nativeEvent.ctrlKey && nativeEvent.altKey);
}

/**
 * Translate native top level events into event types.