date-fns
A comprehensive, modular JavaScript date utility library for manipulating dates in browsers and Node.js.
What is date-fns?
date-fns is a modern JavaScript utility library for manipulating dates and times in both browser and Node.js environments. It provides over 200 functions for parsing, formatting, comparing, and calculating dates, solving the common pain points of working with JavaScript's native Date object. The library is designed to be modular, immutable, and type-safe.
JavaScript and TypeScript developers who need reliable date manipulation in web applications, Node.js backends, or any project requiring consistent date handling.
Developers choose date-fns for its modular architecture, which allows tree-shaking to minimize bundle size, its pure functional approach ensuring predictability, and its first-class TypeScript support with excellent type definitions.
Overview
⏳ Modern JavaScript date utility library ⌛️
Use Cases
Best For
- Formatting and parsing dates in internationalized applications
- Performing complex date calculations like differences or additions
- Building lightweight frontend applications where bundle size matters
- TypeScript projects requiring robust date manipulation with full type safety
- Replacing Moment.js or other legacy date libraries in modern codebases
- Handling time zones and locale-specific date formatting
Not Ideal For
- Projects requiring built-in calendar UI components or interactive date pickers
- Real-time applications where every millisecond counts and native Date manipulation is preferred for performance
- Legacy codebases deeply integrated with Moment.js with complex custom extensions
- Simple scripts or prototypes that only need to display the current date without calculations
Pros & Cons
Pros
Functions can be imported individually, allowing bundlers like webpack to eliminate unused code, which minimizes bundle size as highlighted in the README.
All functions are pure and return new date instances, ensuring predictable behavior and avoiding side effects, making code more reliable.
Written entirely in TypeScript with handcrafted type definitions, providing excellent type safety and developer experience out of the box.
Includes dozens of locales that can be loaded on-demand, facilitating internationalization without bloating the bundle, as mentioned in the features.
Cons
Major version updates like v4.0 introduce breaking changes, such as new time zone APIs, requiring significant refactoring in existing projects, as noted in the blog announcement.
For basic date operations, the pure functional approach can add unnecessary complexity and slight performance overhead compared to direct native Date methods.
With over 200 functions, new users may find the API overwhelming and need time to learn the optimal functions, which can slow down initial adoption.
Open Source Alternative To
date-fns is an open-source alternative to the following products:
Frequently Asked Questions
Related Projects
Day.js⏰ Day.js 2kB immutable date-time library alternative to Moment.js with the same modern API
msTiny millisecond conversion utility
timeago.js:clock8: :hourglass: timeago.js is a tiny(2.0 kb) library used to format date with `*** time ago` statement.
tinytime⏰ A straightforward date and time formatter in <1kb
Found a gem we're missing?
Open-Awesome is built by the community, for the community. Submit a project, suggest an awesome list, or help improve the catalog on GitHub.