Comparing Day.js with Moment.js: Which is Better for Node.js Projects?

As a developer who’s worked extensively with both Day.js and Moment.js in Node.js projects, I’ve gained valuable insights into their strengths and weaknesses. Let’s dive into a detailed comparison to help you make the right choice for your next project.

The Rise of Day.js

Remember when Moment.js was the go-to library for handling dates in JavaScript? Times have changed. Day.js has emerged as a powerful alternative, addressing many of the pain points developers faced with Moment.js. But what makes it special?

Size Matters: Bundle Weight Comparison

One of the most compelling reasons to choose Day.js is its incredibly lightweight nature. While Moment.js weighs in at around 232KB (minified), Day.js is just 2KB! This dramatic difference isn’t just a number – it translates to faster load times and better performance for your applications.

Feature Comparison

Both libraries handle the basics well, but there are some key differences:

Day.js Advantages:

• Immutable by default (no more unexpected date mutations!)
• Modern, chainable API
• Plugin-based architecture for adding only what you need
• Active maintenance and regular updates

Moment.js Status:

• Feature-rich but heavyweight
• Mutable operations (can lead to bugs if you’re not careful)
• Legacy support but no new feature development
• Larger ecosystem of existing solutions

Performance Insights

In my recent projects, I’ve noticed significant performance improvements after switching to Day.js. The lighter bundle size and efficient parsing operations make a real difference, especially in large-scale applications.

Making the Choice

For new projects, Day.js is the clear winner. It’s modern, maintainable, and performant. However, if you’re maintaining a legacy application heavily invested in Moment.js, the migration cost might outweigh the benefits.

Code Migration Example

When migrating, most Moment.js code can be easily converted to Day.js. Here’s a quick example:

const firstDay = moment().startOf('month');

// Day.js
const firstDay = dayjs().startOf('month');

Conclusion

While Moment.js served us well for years, Day.js represents the future of date handling in JavaScript. Its lightweight nature, modern API, and active development make it the superior choice for new Node.js projects in 2024 and beyond.