arraybuffer-encoding
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1.1.0 • Public • Published

npm Node.js CI License: MIT

ArrayBuffer encoding and decoding tools

This package contains utilities to encode and decode ArrayBuffer objects to base64 and hex with full support for Unicode and binary data. It's especially designed for usage in web browsers, but it works on Node.js too.

  • Encode and decode ArrayBuffer objects (and typed arrays like Uint8Array, and strings) to base64 and hex, for the browser and Node.js
  • Supports base64 "standard" and "URL-safe" encodings, with optional padding; custom base64 encodings can be defined as well
  • Clean, well-documented APIs
  • Reasonable performance

Full API documentation available at https://italypaleale.github.io/arraybuffer/

Installation

Install from NPM:

npm i arraybuffer-encoding

Base64

This package offers support for encoding and decoding base64 in two variants:

  • "Standard" base64 (RFC 4648 §4): uses + and / for characters 62 and 63 respectively. Encoded strings have = padding characters added at the end by the Encode function, if necessary.
    Import with:

    import {Encode, Decode} from 'arraybuffer-encoding/base64/standard'

    Can also use arraybuffer-encoding/base64 as alias.

  • URL-safe base64 (RFC 4648 §5): uses - and _ for characters 62 and 63 respectively. Encoded strings are never padded by the Encode function.
    Import with:

    import {Encode, Decode} from 'arraybuffer-encoding/base64/url'

In all cases, the Decode function accepts strings with or without padding.

Encoding to base64

To encode an ArrayBuffer to base64, use the Encode(ab: ArrayBuffer): string method:

import {Encode} from 'arraybuffer-encoding/base64'
const ab = new ArrayBuffer(...)
const encoded = Encode(ab)

Typed arrays, such as Uint8Array objects, can be passed as well:

import {Encode} from 'arraybuffer-encoding/base64'
const array = new Uint8Array(...)
const encoded = Encode(ab)

To encode a UTF-8 string, convert it to a typed array object first:

import {Encode} from 'arraybuffer-encoding/base64'
const str = 'Hello world'
const textEnc = new TextEncoder()
const encoded = Encode(textEnc.encode(str))

Decoding base64

To decode a base64-encoded string, use the Decode(str: string): ArrayBuffer method, which returns an ArrayBuffer object:

import {Decode} from 'arraybuffer-encoding/base64'
const encoded = 'RGV2cw'
const ab = Decode(encoded)

The decoded ArrayBuffer can be converted to a string (for example, UTF-8 encoded) with:

import {Decode} from 'arraybuffer-encoding/base64'
const encoded = 'RGV2cw'
const ab = Decode(encoded)
const textDecoder = new TextDecoder('utf-8')
const str = textDecoder.decode(ab)

Custom base64 charset

If needed, you can define your own base64 charset by using the Encoding class in arraybuffer-encoding/base64/encoding:

import {Encoding} from 'arraybuffer-encoding/base64/encoding'
const base64 = new Encoding(charset, noPadding)

The constructor accepts two parameters:

  • charset: string is a string of 64 characters containing the base64 charset to use
  • noPadding: boolean if true, the Encode method never adds padding at the end of the string (note that the Decode method always considers padding optional)

The object contains two methods:

  • Encode(ab: ArrayBuffer): string
  • Decode(str: string): ArrayBuffer

Hex

To import the hex encoding and decoding utilities, use:

import {Encode, Decode} from 'arraybuffer-encoding/hex'

Encoding to hex

To encode an ArrayBuffer to hex, use the Encode(ab: ArrayBuffer): string method:

import {Encode} from 'arraybuffer-encoding/hex'
const ab = new ArrayBuffer(...)
const encoded = Encode(ab)

Typed arrays, such as Uint8Array objects, can be passed as well:

import {Encode} from 'arraybuffer-encoding/hex'
const array = new Uint8Array(...)
const encoded = Encode(ab)

To encode a UTF-8 string, convert it to a typed array object first:

import {Encode} from 'arraybuffer-encoding/hex'
const str = 'Hello world'
const textEnc = new TextEncoder()
const encoded = Encode(textEnc.encode(str))

Decoding hex

To decode a hex-encoded string, use the Decode(str: string): ArrayBuffer method, which returns an ArrayBuffer object:

import {Decode} from 'arraybuffer-encoding/hex'
const encoded = '54686520717569636b2062726f776e20f09fa68a206a756d7073206f766572203133206c617a7920f09f90b62e'
const ab = Decode(encoded)

The decoded ArrayBuffer can be converted to a string (for example, UTF-8 encoded) with:

import {Decode} from 'arraybuffer-encoding/hex'
const encoded = '54686520717569636b2062726f776e20f09fa68a206a756d7073206f766572203133206c617a7920f09f90b62e'
const ab = Decode(encoded)
const textDecoder = new TextDecoder('utf-8')
const str = textDecoder.decode(ab)

License

This package is released under a MIT license.

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npm i arraybuffer-encoding

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