function calcAge(dobStr) {
// 1: create a new `Date` object from `dobStr`
const birthDate = new Date(dobStr);
// 2: create a new `Date` object for "today"
const today = new Date();
// 3: calculate difference in years between birth year and current year
let age = today.getFullYear() - birthDate.getFullYear();
// 4: calculate difference in months between birth month and current month
const monthDifference = today.getMonth() - birthDate.getMonth();
if (
// 5.1: current month is earlier than the birth month?
monthDifference < 0
// 5.2: or, same month but current day is earlier than birth day?
|| (monthDifference === 0 && today.getDate() < birthDate.getDate())
) {
// 5.3: subtract `1` from the age
age--;
}
// 6: return calculated age
return age;
}
console.log(calcAge('1980-05-05'));
console.log(calcAge('1910-07-16'));
console.log(calcAge('2020-02-24'));
console.log(calcAge('2023-01-01'));
// ...
This post was published by Daniyal Hamid. Daniyal currently works as the Head of Engineering in Germany and has 20+ years of experience in software engineering, design and marketing. Please show your love and support by sharing this post.