[javascript] 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?

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'.

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.

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 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;
}

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]

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

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');

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)

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).