const voted = {};

/**
 * Vote check
 * @param {string} name Voter name
 */
const checkVoter = name => {
  if (voted[name]) {
    console.log("kick them out!");
  } else {
    voted[name] = true;
    console.log("let them vote!");
  }
};

checkVoter("tom"); // let them vote!
checkVoter("mike"); // let them vote!
checkVoter("mike"); // kick them out!