dayjs

Fast, 2KB date library for JavaScript — a Moment.js-compatible API with a tiny footprint and plugin system.

dayjs

General JS

Fast, 2KB date library for JavaScript — a Moment.js-compatible API with a tiny footprint and plugin system.

npm GitHub Docs

Fit

Bundle (gzip)

3.0 kB

7.1 kB raw

Install size includes transitive dependencies. Bundle size is gzipped browser payload.

Freshness

The Problem

Moment.js is mutable, over 66KB minified, and no longer actively developed. The native Date API lacks formatting, relative time, timezone support, and chainable manipulation methods.

What It Does

Day.js parses, validates, manipulates, and formats dates with an API nearly identical to Moment.js. It's immutable by default, weighs ~2KB, and extends via plugins (timezone support, relative time, ISO week, etc.) that are only loaded when needed.

Installation

bash

npm install dayjs

Usage Example

typescript

import dayjs from 'dayjs';
import relativeTime from 'dayjs/plugin/relativeTime';
import timezone from 'dayjs/plugin/timezone';
import utc from 'dayjs/plugin/utc';

dayjs.extend(relativeTime);
dayjs.extend(utc);
dayjs.extend(timezone);

dayjs('2025-01-15').format('MMMM D, YYYY');     // 'January 15, 2025'
dayjs().subtract(3, 'day').fromNow();            // '3 days ago'
dayjs().tz('America/New_York').format('h:mm A'); // '9:30 AM'
dayjs('2025-01-01').isBefore('2025-06-01');      // true

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