3 examples of 'calculate date of birth from age in javascript' in JavaScript

52
export function ageAsOf(birthDate, date) {
53
  if (!birthDate || !date || !birthDate.isValid() || !date.isValid()) {
54
    return null;
55
  }
56
57
  const onOrAfterBirthday = (
58
    date.month() > birthDate.month() || (
59
      date.month() === birthDate.month()
60
      && date.date() >= birthDate.date()
61
    )
62
  );
63
64
  return (date.year() - birthDate.year() - (onOrAfterBirthday ? 0 : 1));
65
}

1
function age(birthday) {
2
  var ageDifMs = Date.now() - birthday.getTime();
3
  var ageDate = new Date(ageDifMs);
4
  return Math.abs(ageDate.getUTCFullYear() - 1970);
5
}

5
public getAge(): number {
6
    return moment().diff(moment(this.value), "years");
7
}