When working with dates and time in JavaScript, Moment.js is a popular library that provides a variety of helpful utilities. One common task is calculating the difference in years between two moments. In this blog post, we will explore how to use Moment.js to achieve this.

Prerequisites

Before diving into the actual implementation, make sure you have Moment.js installed in your project. You can include it by adding the following script tag to your HTML file:

<script src="https://cdn.jsdelivr.net/momentjs/latest/moment.min.js"></script>

Alternatively, you can install Moment.js using a package manager like npm:

npm install moment

Once you have Moment.js set up, you are ready to calculate the number of years between two moments.

Calculating the difference in years

First, you need to create two Moment.js objects representing the two moments you want to calculate the difference between. You can create a moment object by passing in a date string and format to the moment() function. For example:

const moment1 = moment("2020-01-01", "YYYY-MM-DD");
const moment2 = moment("2022-12-31", "YYYY-MM-DD");

Once you have the two moments, you can use the diff() function to calculate the difference between them. By default, diff() returns the difference in milliseconds, but you can specify a different unit of measurement. To calculate the difference in years, pass the "years" argument to the diff() function:

const yearsDiff = moment2.diff(moment1, "years");

You now have the number of years between the two moments stored in the yearsDiff variable.

Example

Here’s a complete example that demonstrates calculating the number of years between two moments:

const moment1 = moment("2020-01-01", "YYYY-MM-DD");
const moment2 = moment("2022-12-31", "YYYY-MM-DD");

const yearsDiff = moment2.diff(moment1, "years");

console.log(yearsDiff); // Output: 2

Conclusion

Moment.js provides a simple and convenient way to calculate the difference in years between two moments. By following the steps outlined in this blog post, you can easily perform this task in your JavaScript projects. Remember to include Moment.js in your project and create moment objects representing the two moments you want to compare.