age.js

var age = function age() {
  var dob = new Date(this.dob);
  var today = new Date();
  var thisYear = today.getFullYear();
  if (dob.getMonth() > today.getMonth() ||
      dob.getMonth() === today.getMonth() &&
      dob.getDate() >= today.getDate()) {
    thisYear -= 1;
  }
  return thisYear - dob.getFullYear();
};