On 01.09.2026 is-animated library got massive overhaul and switched the repository it's built from (we're now using fork created by FRSOURCE team).

For more information, see Migration note.

Quick start

Installation

npm install is-animated

yarn add is-animated

pnpm add is-animated

Usage in browser

<input type="file" accept="image/*" />

import isAnimated from 'is-animated';

const input = document.querySelector('input[type="file"]');

input.addEventListener('change', async function () {
  const arrayBuffer = await this.files[0].arrayBuffer();
  const answer = isAnimated(arrayBuffer) ? 'IS' : 'IS NOT';
  alert(`File "${this.files[0].name}" ${answer} animated.`);
});

If you prefer, you can import this library using unpkg: <script defer src="https://unpkg.com/is-animated"></script>

Usage in Node.js

import { readFileSync } from 'fs';
import isAnimated from 'is-animated';

readFileSync('my-test-file.png', (err, buffer) => {
  const answer = isAnimated(buffer) ? 'IS' : 'IS NOT';
  console.log(`File "my-test-file.png" ${answer} animated.`);
});

Demo

For a working example, check out our demo.

Questions

Don’t hesitate to ask a question directly on the discussion board!

Changelog

Changes for every release are documented in the release notes and CHANGELOG file.

Migration from 2.x.x

On 01.09.2026 the library got upgraded using source from FRSOURCE fork which also became the new maintenance team!

Version 3:

• adds support for running is-animated under browser environment,
• adds support for AVIF format,
• adds support for ESM modules (.mjs),
• drops support for CommonJS,
• drops support for Node below version 20.

Migration path consists of two things: migrate to Node.js >= 20 and switch from CommonJS to ESM.

Everything else (whole API) stays the same. Enjoy!

Development

1. Check out the repository.
2. Install dependencies using pnpm i.
3. Run pnpm test to run the test suite.
4. Run pnpm start and visit http://localhost:3000 to see the documentation page. You can test the library using the demo section.

License

MIT @ 2024-present, Jakub FRS Freisler, FRSOURCE

MIT @ 2019-2024, Józef Sokołowski

Forked from qzb's great library: is-animated.