Moment.js - how do I get the number of years since a date, not rounded up?

I'm trying to calculate a person's age using Moment.js, but I'm finding that the otherwise useful fromNow method rounds up the years. For instance, if today is 12/27/2012 and the person's birth date is 02/26/1978, moment("02/26/1978", "MM/DD/YYYY").fromNow() returns '35 years ago'. How can I make Moment.js ignore the number of months, and simply return the number of years (i.e. 34) since the date?

Using moment.js is as easy as:

var years = moment().diff('1981-01-01', 'years');
var days = moment().diff('1981-01-01', 'days');

For additional reference, you can read moment.js official documentation.

http://jsfiddle.net/xR8t5/27/

if you do not want fraction values:

var years = moment().diff('1981-01-01', 'years',false);
alert( years);

if you want fraction values:

var years = moment().diff('1981-01-01', 'years',true);
alert( years);

Units can be [seconds, minutes, hours, days, weeks, months, years]

There appears to be a difference function that accepts time intervals to use as well as an option to not round the result. So, something like

Math.floor(moment(new Date()).diff(moment("02/26/1978","MM/DD/YYYY"),'years',true)))

I haven't tried this, and I'm not completely familiar with moment, but it seems like this should get what you want (without having to reset the month).

This method is easy and powerful.

Value is a date and "DD-MM-YYYY" is the mask of the date.

moment().diff(moment(value, "DD-MM-YYYY"), 'years');

I found that it would work to reset the month to January for both dates (the provided date and the present):

> moment("02/26/1978", "MM/DD/YYYY").month(0).from(moment().month(0))
"34 years ago"

Try this:

 moment("02/26/1978", "MM/DD/YYYY").fromNow().split(" ")[0];

Explanation:

We receive string something like this: '23 days ago'. Split it to array: ['23', 'days', 'ago'] and then take first item '23'.

This method works for me. It's checking if the person has had their birthday this year and subtracts one year otherwise.

// date is the moment you're calculating the age of
var now = moment().unix();
var then = date.unix();
var diff = (now - then) / (60 * 60 * 24 * 365);
var years = Math.floor(diff);

Edit: First version didn't quite work perfectly. The updated one should

If you dont want to use any module for age calculation

var age = Math.floor((new Date() - new Date(date_of_birth)) / 1000 / 60 / 60 / 24 / 365.25)

When you want to show years and the remaining days:

var m = moment(d.birthday.date, "DD.MM.YYYY");
var years = moment().diff(m, 'years', false);
var days = moment().diff(m.add(years, 'years'), 'days', false);
alert(years + ' years, ' + days + ' days');

I prefer this small method.

function getAgeFromBirthday(birthday) {
    if(birthday){
      var totalMonths = moment().diff(birthday, 'months');
      var years = parseInt(totalMonths / 12);
      var months = totalMonths % 12;
        if(months !== 0){
           return parseFloat(years + '.' + months);
         }
    return years;
      }
    return null;
}

Get years and days using moment.js library

import moment from 'moment'

export function getAge(dateString: string) {
  const date = moment(dateString, 'YYYY-MM-DD')
  const years = moment().diff(date, 'years')
  const days = moment().diff(date.add(years, 'years'), 'days', false)
  return { years, days }
}

const birthDate = "1997-04-01T00:00:00.000Z";
const age = getAge(birthDate);

// Today is 2022-04-09
console.log({ age })
// Result: { age: { years: 25, days: 8 } }