# Is dayjs ESM-only? Can you require() it?

> dayjs@1.11.23 is a CommonJS package. CommonJS — require() works on every Node.js version we test.

2KB immutable date time library alternative to Moment.js with the same modern API 

Last verified Sep 9, 2026 against dayjs@1.11.23.

dayjs ships CommonJS only. require("dayjs") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "dayjs" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

## What to do

1. require("dayjs") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun.
2. From ES modules use the default import: import dayjs from "dayjs"; then destructure. Named imports only work when Node.js can statically detect the exports.
3. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 1.11.23 (Aug 17, 2026)
- Module format: CommonJS
- Last CommonJS version: 1.11.23
- TypeScript types: bundled
- Node engines: not declared
- Weekly downloads: 48.7M
- License: MIT

## Runtime test results for dayjs@1.11.23

Installed and executed on Sep 9, 2026 with require("dayjs") from a CommonJS file and import "dayjs" from an ES module.

| Runtime | require("dayjs") | import "dayjs" |
|---|---|---|
| Node.js 18 | works | works |
| Node.js 20 | works | works |
| Node.js 22 | works | works |
| Node.js 24 | works | works |
| Node.js 26 | works | works |
| Bun 1.4.0 | works | works |

## How to import dayjs

ES modules:

```js
import dayjs from "dayjs";
```

CommonJS:

```js
const dayjs = require("dayjs");
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (132 versions; the newest 60 shown).

| Versions | Format | First published |
|---|---|---|
| 1.8.19 – 1.11.23 | CommonJS | Jan 6, 2020 |

## Frequently asked

**Is dayjs ESM-only?**

dayjs@1.11.23 is a CommonJS package. dayjs ships CommonJS only. require("dayjs") works on every Node.js version we test (18, 20, 22, 24 and 26) and in Bun. import "dayjs" also works because Node.js and Bun can import CommonJS from ES modules, but only the default export is guaranteed; named imports depend on Node's static analysis of the module.

**Can I import dayjs with ES module syntax?**

Yes. import dayjs from "dayjs" works in Node.js and Bun because they support importing CommonJS modules. Named imports work only when Node.js can statically detect the exports.

**Does dayjs work in Bun?**

Yes. import "dayjs" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does dayjs ship TypeScript types?**

Yes. dayjs bundles its own type declarations; no @types package is needed.

## Links

- [dayjs on npm](https://www.npmjs.com/package/dayjs)
- [Source repository](https://github.com/iamkun/dayjs)
- [HTML version](https://canirequire.com/package/dayjs/)
- [JSON version](https://canirequire.com/package/dayjs.json)

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