swansontecrfc4648.js
This library implements encoding and decoding for the data formats specified in rfc4648:
- base64
- base64url
- base32
- base32hex
- base16
Each encoding has a simple API inspired by Javascript's built-in JSON object:
import { base32 } from "rfc4648";
base32.stringify([42, 121, 160]); // -> 'FJ42A==='
base32.parse("FJ42A==="); // -> Uint8Array([42, 121, 160])
The library has tree-shaking support, so tools like rollup.js or Webpack 2+ can automatically trim away any encodings you don't use.
- Zero external dependencies
- 100% test coverage
- Built-in types for Typescript & Flow
- 0.8K minified + gzip (can be even smaller with tree shaking)
API details
The library provides the following top-level modules:
base64base64urlbase32base32hexbase16codec
Each module exports a parse and stringify function.
const string = baseXX.stringify(data, opts)
Each stringify function takes array-like object of bytes and returns a string.
If you pass the option { pad: false } in the second parameter, the encoder will not output padding characters (=).
const data = baseXX.parse(string, opts)
Each parse function takes a string and returns a Uint8Array of bytes. If you would like a different return type, such as plain Array or a Node.js Buffer, pass its constructor in the second argument:
base64.parse("AOk=", { out: Array });
base64.parse("AOk=", { out: Buffer.allocUnsafe });
The constructor will be called with new, and should accept a single integer for the output length, in bytes.
If you pass the option { loose: true } in the second parameter, the parser will not validate padding characters (=):
base64.parse("AOk", { loose: true }); // No error
The base32 codec will also fix common typo characters in loose mode:
base32.parse("He1l0==", { loose: true }); // Auto-corrects as 'HELLO==='
Custom encodings
To define your own encodings, use the codec module:
const codec = require("rfc4648").codec;
const myEncoding = {
chars: "01234567",
bits: 3
};
codec.stringify([220, 10], myEncoding); // '670050=='
codec.parse("670050", myEncoding, { loose: true }); // [ 220, 10 ]
The encoding structure should have two members, a chars member giving the alphabet and a bits member giving the bits per character. The codec.parse function will extend this with a third member, codes, the first time it's called. The codes member is a lookup table mapping from characters back to numbers.