How to Find Numeric Difference Between Two Dates in MomentJS?

To find the numeric difference between two dates using MomentJS, you would typically need to first parse the dates into MomentJS objects. Then, you calculate the difference between these two dates. This difference is usually represented as a numeric value, indicating the quantity of a specific unit of time (like days, months, or years) separating the two dates. To obtain this value, MomentJS provides methods that compute the difference based on the units of time you specify.

These are the following ways to find the numeric difference between two dates in MomentJS:”

Using the .diff() Method

The diff() method is another function in Moment which has been discussed above. js that tells the number of years, months, days, hours, minutes, or seconds between two dates. This method returns the difference in the form of a number meaning that it well suitable for numerical computation.

Syntax:

moment(date1).diff(moment(date2), 'unit');

Example: This code calculates and logs the difference in days between two dates using MomentJS.

const moment = require('moment');

const date1 = moment("2024-08-20");
const date2 = moment("2024-07-20");

const differenceInDays = date1.diff(date2, 'days');
console.log(`Difference in days: ${differenceInDays}`);

Output:

Difference in days: 31

Using Custom Calculations

Sometimes, it is required to work with the existence of some variable between two days: either exclude weekends or include weekdays only. For such situations, there are the possibilities to use the custom calculations and to go through the dates, applying your logic.

Syntax:

let difference = 0;
while (moment(date1).isAfter(date2)) {
    // Custom logic to increment difference
    difference++;
    date2.add(1, 'days');
}

Example: This code calculates the number of weekdays between two dates, excluding weekends, by iterating through each day between them.

const moment = require('moment');

let date1 = moment("2024-08-20");
let date2 = moment("2024-07-20");

let weekdayDifference = 0;

while (date2.isBefore(date1)) {
    if (date2.isoWeekday() !== 6 && 
        date2.isoWeekday() !== 7) { // Excluding weekends
        weekdayDifference++;
    }
    date2.add(1, 'days');
}

console.log(`Weekday difference: ${weekdayDifference}`);

Output:

Weekday difference: 22

Using Relative Time Formats

MomentJS also has relative time formats that get the human elapsed time, like “3 days ago”, “in 2 weeks” and the like, which will be useful if you need to display it to the user.

Syntax:

moment(date1).from(moment(date2));

Example: This code calculates and logs the number of days between two dates using MomentJS.

const moment = require('moment');

const date1 = moment("2024-08-20");
const date2 = moment("2024-07-20");

const relativeDifference = date1.from(date2);
console.log(`Relative difference: ${relativeDifference}`);

Output:

Relative difference: in a month

Conclusion

In web development, determining the difference between two dates is a common requirement, and MomentJS provides a straightforward solution for this task. Using MomentJS, you can easily compute the difference in days, months, or other units with its .diff() method, which simplifies date calculations and offers flexibility for various needs. Additionally, MomentJS supports custom calculations and relative time formatting, enhancing its utility for specific requirements and presenting results in a user-friendly manner.