comm-cohesion2.js

const RETIREMENT_AGE = 65;

function calculateAge(birthday) {
  let ageDifMs = Date.now() - birthday.getTime();
  let ageDate = new Date(ageDifMs); // miliseconds from epoch
  return Math.abs(ageDate.getUTCFullYear() - 1970)
}

function calcRetirementTime(age) {
  return RETIREMENT_AGE - age;
}

function timeToRetire(birthday) { // birthday is a date
  let age = calculateAge(birthday);
  let _timeToRetire = calcRetirementTime(age);
  return _timeToRetire;
}