function keyNameFromEvent(event) {
  const customKeyCodes = Configuration.option('customKeyCodes');

  // noinspection JSDeprecatedSymbols
  const keyCode = event.keyCode || event.charCode;

  if (hasKey(customKeyCodes, keyCode)) {
    return customKeyCodes[keyCode];
  }

  if (event.nativeEvent) {
    return event.key;
  } else {
    return reactsGetEventKey(event);
  }
}
Lowercased string representing a particular keyboard key
@typedef {string} NormalizedKeyName