const calcAge = function (birthYear) {
  return new Date().getFullYear() - birthYear;
};

const yearsUntilRetirement = (birthYear, firstName) => {
  const age = calcAge(birthYear);
  const retirement = 65 - age;

  if (retirement > 0) {
    console.log(`${firstName} retires in ${retirement} years`);
    return retirement;
  } else {
    console.log(`${firstName} is already retired`);
    return -1;
  }
  //   return `${firstName} retires in ${retirement} years`;
};

console.log(yearsUntilRetirement(1986, "David"));
console.log(yearsUntilRetirement(1950, "David"));