Difference between two dates in years, months, days in JavaScript

Question

I\'ve been searching for 4 hours now, and have not found a solution to get the difference between two dates in years, months, and days in JavaScript, like: 10th of April 201

Answer 1

Its very simple please use the code below and it will give the difference in that format according to this //3 years 9 months 3 weeks 5 days 15 hours 50 minutes

Date.getFormattedDateDiff = function(date1, date2) {
var b = moment(date1),
  a = moment(date2),
  intervals = ['years','months','weeks','days'],
  out = [];

for(var i=0; i<intervals.length; i++){
  var diff = a.diff(b, intervals[i]);
  b.add(diff, intervals[i]);
  out.push(diff + ' ' + intervals[i]);
 }
 return out.join(', ');
 };

 var today   = new Date(),
 newYear = new Date(today.getFullYear(), 0, 1),
 y2k     = new Date(2000, 0, 1);

 //(AS OF NOV 29, 2016)
 //Time since New Year: 0 years, 10 months, 4 weeks, 0 days
 console.log( 'Time since New Year: ' + Date.getFormattedDateDiff(newYear, today) );

 //Time since Y2K: 16 years, 10 months, 4 weeks, 0 days
 console.log( 'Time since Y2K: ' + Date.getFormattedDateDiff(y2k, today) );

Answer 2

I've stumbled upon this while having the same problem. Here is my code. It totally relies on the JS date function, so leap years are handled, and does not compare days based on hours, so it avoids daylight saving issues.

function dateDiff(start, end) {
    let years = 0, months = 0, days = 0;
    // Day diffence. Trick is to use setDate(0) to get the amount of days
    // from the previous month if the end day less than the start day.
    if (end.getDate() < start.getDate()) {
        months = -1;
        let datePtr = new Date(end);
        datePtr.setDate(0);
        days = end.getDate() + (datePtr.getDate() - start.getDate());
    } else {
        days = end.getDate() - start.getDate();
    }

    if (end.getMonth() < start.getMonth() ||
       (end.getMonth() === start.getMonth() && end.getDate() < start.getDate())) {
        years = -1;
        months += end.getMonth() + (12 - start.getMonth());
    } else {
        months += end.getMonth() - start.getMonth();
    }

    years += end.getFullYear() - start.getFullYear();
    console.log(`${years}y ${months}m ${days}d`);
    return [years, months, days];
}

Answer 3

How precise do you need to be? If you do need to take into account common years and leap years, and the exact difference in days between months then you'll have to write something more advanced but for a basic and rough calculation this should do the trick:

today = new Date()
past = new Date(2010,05,01) // remember this is equivalent to 06 01 2010
//dates in js are counted from 0, so 05 is june

function calcDate(date1,date2) {
    var diff = Math.floor(date1.getTime() - date2.getTime());
    var day = 1000 * 60 * 60 * 24;

    var days = Math.floor(diff/day);
    var months = Math.floor(days/31);
    var years = Math.floor(months/12);

    var message = date2.toDateString();
    message += " was "
    message += days + " days " 
    message += months + " months "
    message += years + " years ago \n"

    return message
    }


a = calcDate(today,past)
console.log(a) // returns Tue Jun 01 2010 was 1143 days 36 months 3 years ago

Keep in mind that this is imprecise, in order to calculate the date with full precision one would have to have a calendar and know if a year is a leap year or not, also the way I'm calculating the number of months is only approximate.

But you can improve it easily.

Answer 4

by using Moment library and some custom logic, we can get the exact date difference

var out;

out = diffDate(new Date('2014-05-10'), new Date('2015-10-10'));
display(out);

out = diffDate(new Date('2014-05-10'), new Date('2015-10-09'));
display(out);

out = diffDate(new Date('2014-05-10'), new Date('2015-09-09'));
display(out);

out = diffDate(new Date('2014-05-10'), new Date('2015-03-09'));
display(out);

out = diffDate(new Date('2014-05-10'), new Date('2016-03-09'));
display(out);

out = diffDate(new Date('2014-05-10'), new Date('2016-03-11'));
display(out);

function diffDate(startDate, endDate) {
  var b = moment(startDate),
    a = moment(endDate),
    intervals = ['years', 'months', 'weeks', 'days'],
    out = {};

  for (var i = 0; i < intervals.length; i++) {
    var diff = a.diff(b, intervals[i]);
    b.add(diff, intervals[i]);
    out[intervals[i]] = diff;
  }
  return out;
}

function display(obj) {
  var str = '';
  for (key in obj) {
    str = str + obj[key] + ' ' + key + ' '
  }
  console.log(str);
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.24.0/moment.js"></script>

Answer 5

I used this simple code to get difference in Years, Months, days with current date.

var sdt = new Date('1972-11-30');
var difdt = new Date(new Date() - sdt);
alert((difdt.toISOString().slice(0, 4) - 1970) + "Y " + (difdt.getMonth()+1) + "M " + difdt.getDate() + "D");

Answer 6

Using Plane Javascript:

function dateDiffInDays(start, end) {
    var MS_PER_DAY = 1000 * 60 * 60 * 24;
    var a = new Date(start);
    var b = new Date(end);

    const diffTime = Math.abs(a - b);
    const diffDays = Math.ceil(diffTime / MS_PER_DAY); 
    console.log("Days: ", diffDays);

    // Discard the time and time-zone information.
    const utc1 = Date.UTC(a.getFullYear(), a.getMonth(), a.getDate());
    const utc2 = Date.UTC(b.getFullYear(), b.getMonth(), b.getDate());
    return Math.floor((utc2 - utc1) / MS_PER_DAY);
}

function dateDiffInDays_Months_Years(start, end) {
    var m1 = new Date(start);
    var m2 = new Date(end);
    var yDiff = m2.getFullYear() - m1.getFullYear();
    var mDiff = m2.getMonth() - m1.getMonth();
    var dDiff = m2.getDate() - m1.getDate();

    if (dDiff < 0) {
        var daysInLastFullMonth = getDaysInLastFullMonth(start);
        if (daysInLastFullMonth < m1.getDate()) {
            dDiff = daysInLastFullMonth + dDiff + (m1.getDate() - 

daysInLastFullMonth);
        } else {
            dDiff = daysInLastFullMonth + dDiff;
        }
        mDiff--;
    }
    if (mDiff < 0) {
        mDiff = 12 + mDiff;
        yDiff--;
    }
    console.log('Y:', yDiff, ', M:', mDiff, ', D:', dDiff);
}
function getDaysInLastFullMonth(day) {
    var d = new Date(day);
    console.log(d.getDay() );

    var lastDayOfMonth = new Date(d.getFullYear(), d.getMonth() + 1, 0);
    console.log('last day of month:', lastDayOfMonth.getDate() ); //

    return lastDayOfMonth.getDate();
}

Using moment.js:

function dateDiffUsingMoment(start, end) {
    var a = moment(start,'M/D/YYYY');
    var b = moment(end,'M/D/YYYY');
    var diffDaysMoment = b.diff(a, 'days');
    console.log('Moments.js : ', diffDaysMoment);

    preciseDiffMoments(a,b);
}
function preciseDiffMoments( a, b) {
    var m1= a, m2=b;
    m1.add(m2.utcOffset() - m1.utcOffset(), 'minutes'); // shift timezone of m1 to m2
    var yDiff = m2.year() - m1.year();
    var mDiff = m2.month() - m1.month();
    var dDiff = m2.date() - m1.date();
    if (dDiff < 0) {
        var daysInLastFullMonth = moment(m2.year() + '-' + (m2.month() + 1), 

"YYYY-MM").subtract(1, 'M').daysInMonth();
        if (daysInLastFullMonth < m1.date()) { // 31/01 -> 2/03
            dDiff = daysInLastFullMonth + dDiff + (m1.date() - 

daysInLastFullMonth);
        } else {
            dDiff = daysInLastFullMonth + dDiff;
        }
        mDiff--;
    }
    if (mDiff < 0) {
        mDiff = 12 + mDiff;
        yDiff--;
    }
    console.log('getMomentum() Y:', yDiff, ', M:', mDiff, ', D:', dDiff);
}

Tested the above functions using following samples:

var sample1 = all('2/13/2018', '3/15/2018'); // {'M/D/YYYY'} 30, Y: 0 , M: 1 , D: 2
console.log(sample1);

var sample2 = all('10/09/2019', '7/7/2020'); // 272, Y: 0 , M: 8 , D: 29
console.log(sample2);

function all(start, end) {
    dateDiffInDays(start, end);
    dateDiffInDays_Months_Years(start, end);

    try {
        dateDiffUsingMoment(start, end);
    } catch (e) {
        console.log(e); 
    }
}