How to Parse and Manipulate Dates in Node.js Using Day.js

Working with dates in JavaScript has always been a bit tricky. While the native Date object gets the job done, it often leaves developers wanting more flexibility and convenience. Enter Day.js – a lightweight and modern library that makes date manipulation a breeze in Node.js applications.

Why Choose Day.js?

Day.js has become a popular choice among developers for several compelling reasons. At just 2KB minified and gzipped, it’s incredibly lightweight compared to alternatives like Moment.js. Despite its small size, it provides a powerful API that’s both intuitive and chainable. Plus, its modular architecture means you only import what you need.

Getting Started with Day.js

First, let’s install Day.js in your Node.js project:

npm install dayjs

Now, let’s explore some common use cases and see how Day.js makes date manipulation effortless.

Basic Date Operations

const dayjs = require('dayjs');

// Get current date
const now = dayjs();
console.log(now.format('YYYY-MM-DD HH:mm:ss'));

// Create a specific date
const christmas = dayjs('2024-12-25');
console.log(christmas.format('dddd, MMMM D, YYYY'));

Advanced Date Manipulation

One of Day.js’s strengths is its intuitive API for adding, subtracting, and comparing dates:

const futureDate = dayjs().add(1, 'month').subtract(2, 'days');
console.log(futureDate.format('MM/DD/YYYY'));

// Check if a date is before another
const isBefore = dayjs('2024-01-01').isBefore('2024-12-31');
console.log('Is before:', isBefore);

// Calculate difference between dates
const diff = dayjs('2024-12-31').diff(dayjs('2024-01-01'), 'days');
console.log('Days difference:', diff);

Working with Timezones

Day.js handles timezones gracefully with the help of plugins:

const utc = require('dayjs/plugin/utc');
const timezone = require('dayjs/plugin/timezone');
dayjs.extend(utc);
dayjs.extend(timezone);

const tokyoTime = dayjs().tz('Asia/Tokyo');
console.log('Tokyo time:', tokyoTime.format());

Best Practices and Tips

1. Always chain operations for cleaner code
2. Use appropriate plugins for extended functionality
3. Format dates consistently throughout your application
4. Consider locale support for international applications

Remember that Day.js is immutable – operations return new objects instead of modifying existing ones. This helps prevent bugs and makes your code more predictable.

Conclusion

Day.js proves that working with dates doesn’t have to be complicated. Its intuitive API, small footprint, and powerful features make it an excellent choice for Node.js developers who want to handle dates efficiently without the overhead of larger libraries.