function checkKeyCodes (
  eventKeyCode,
  key,
  builtInAlias
) {
  var keyCodes = config.keyCodes[key] || builtInAlias;
  if (Array.isArray(keyCodes)) {
    return keyCodes.indexOf(eventKeyCode) === -1
  } else {
    return keyCodes !== eventKeyCode
  }
}
Runtime helper for checking keyCodes from config.