A JavaScript module that implements window.atob and window.btoa according the forgiving-base64 algorithm in the Infra Standard. The original code was forked from w3c/web-platform-tests.

Compatibility: Node.js version 3+ and all major browsers.

Install with npm:

npm install abab

API

<tt>btoa</tt> (base64 encode)

const { btoa } = require('abab');

btoa('Hello, world!'); // 'SGVsbG8sIHdvcmxkIQ=='

<tt>atob</tt> (base64 decode)

const { atob } = require('abab');

atob('SGVsbG8sIHdvcmxkIQ=='); // 'Hello, world!'

Valid characters

Per the spec, btoa will accept strings "containing only characters in the range `U+0000` to `U+00FF`." If passed a string with characters above U+00FF, btoa will return null. If atob is passed a string that is not base64-valid, it will also return null. In both cases when null is returned, the spec calls for throwing a DOMException of type InvalidCharacterError.

Browsers

If you want to include just one of the methods to save bytes in your client-side code, you can require the desired module directly.

const atob = require('abab/lib/atob');

const btoa = require('abab/lib/btoa');

Development

If you're submitting a PR or deploying to npm, please use the checklists in CONTRIBUTING.md.

Remembering what <tt>atob</tt> and <tt>btoa</tt> stand for

Base64 comes from IETF RFC 4648 (2006).

**btoa**, the encoder function, stands for binary to ASCII, meaning it converts any binary input into a subset of ASCII (Base64).
**atob**, the decoder function, converts ASCII (or Base64) to its original binary format.