rfc4648

What is rfc4648?

The rfc4648 npm package provides utilities for encoding and decoding data in Base16, Base32, and Base64 formats, adhering to the specifications outlined in RFC 4648.

What are rfc4648's main functionalities?

Base16 Encoding

This feature allows you to encode data into Base16 (hexadecimal) format. The code sample demonstrates encoding a Uint8Array into a Base16 string.

const rfc4648 = require('rfc4648');
const data = new Uint8Array([72, 101, 108, 108, 111]);
const encoded = rfc4648.base16.stringify(data);
console.log(encoded); // Outputs: 48656C6C6F

Base16 Decoding

This feature allows you to decode Base16 (hexadecimal) strings back into their original data format. The code sample demonstrates decoding a Base16 string into a Uint8Array.

const rfc4648 = require('rfc4648');
const encoded = '48656C6C6F';
const decoded = rfc4648.base16.parse(encoded);
console.log(decoded); // Outputs: Uint8Array(5) [ 72, 101, 108, 108, 111 ]

Base32 Encoding

This feature allows you to encode data into Base32 format. The code sample demonstrates encoding a Uint8Array into a Base32 string.

const rfc4648 = require('rfc4648');
const data = new Uint8Array([72, 101, 108, 108, 111]);
const encoded = rfc4648.base32.stringify(data);
console.log(encoded); // Outputs: JBSWY3DP

Base32 Decoding

This feature allows you to decode Base32 strings back into their original data format. The code sample demonstrates decoding a Base32 string into a Uint8Array.

const rfc4648 = require('rfc4648');
const encoded = 'JBSWY3DP';
const decoded = rfc4648.base32.parse(encoded);
console.log(decoded); // Outputs: Uint8Array(5) [ 72, 101, 108, 108, 111 ]

Base64 Encoding

This feature allows you to encode data into Base64 format. The code sample demonstrates encoding a Uint8Array into a Base64 string.

const rfc4648 = require('rfc4648');
const data = new Uint8Array([72, 101, 108, 108, 111]);
const encoded = rfc4648.base64.stringify(data);
console.log(encoded); // Outputs: SGVsbG8=

Base64 Decoding

This feature allows you to decode Base64 strings back into their original data format. The code sample demonstrates decoding a Base64 string into a Uint8Array.

const rfc4648 = require('rfc4648');
const encoded = 'SGVsbG8=';
const decoded = rfc4648.base64.parse(encoded);
console.log(decoded); // Outputs: Uint8Array(5) [ 72, 101, 108, 108, 111 ]

Other packages similar to rfc4648

base-x

The base-x package provides utilities for encoding and decoding data in various base formats, including Base16, Base32, and Base64. It is highly customizable and allows for defining custom alphabets for encoding. Compared to rfc4648, base-x offers more flexibility in terms of custom base encoding but may require more configuration for standard use cases.

base64-js

The base64-js package focuses specifically on Base64 encoding and decoding. It is lightweight and optimized for performance. Compared to rfc4648, base64-js is more specialized and may be a better choice if you only need Base64 functionality without the additional Base16 and Base32 support.

js-base64

The js-base64 package provides Base64 encoding and decoding utilities with a simple API. It is widely used and well-documented. Compared to rfc4648, js-base64 is more user-friendly and may be easier to integrate for projects that only require Base64 encoding and decoding.

README

rfc4648.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
• 0.8K minified + gzip (can be even smaller with tree shaking)

API details

The library provides the following top-level modules:

• base64
• base64url
• base32
• base32hex
• base16
• codec

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:

base64.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.