@lib/utf-8

This is a well-tested UTF-8 encoder / decoder with some distinctive features:

• Very small when minified.
• Forgiving with invalid inputs.
  • Any JavaScript string will remain identical after encoding and decoding, even if the string itself is invalid UTF-16. See WTF-8 encoding.
  • Overlong UTF-8 sequences of up to 6 bytes are allowed.
• Detects unrecoverably corrupt UTF-8 input.
  • Runs of unexpected continuation bytes, or a start byte followed by insufficient continuation bytes, become replacement character fffd.
• Handles astral plane characters like emoji.
• Supports reading from and writing into existing buffers using given offsets.
• Written in TypeScript.

Installation

From npm and Node.js:

npm install --save @lib/utf-8

var utf8 = require('@lib/utf-8');

From CDN in HTML:

<script src="https://cdn.jsdelivr.net/npm/@lib/utf-8@0.1/bundle.js"></script>

Using RequireX:

import * as utf8 from '@lib/utf-8';

Usage

// Prints: 194, 189
console.log(utf8.encodeUTF8('½').join(', '));

// Prints: ½
console.log(utf8.decodeUTF8([194, 189]));

API

encodeUTF8(src, dst?, dstPos?, srcPos?, srcEnd?)

UTF-8 encode a string to an array of bytes. This transform cannot fail and is reversible for any input string, regardless of strange or invalid characters (handled using WTF-8).

• src String to encode.
• dst Destination array or buffer for storing the result.
• dstPos Initial offset to destination, default is 0.
• srcPos Initial offset to source data, default is 0.
• srcEnd Source data end offset, default is its length.

Returns end offset past data stored if a destination was given, otherwise a numeric array containing the encoded result. Note that output length cannot exceed 3 * input length.

decodeUTF8(src, dst?, srcPos?, srcEnd?)

UTF-8 decode an array of bytes into a string. Invalid surrogate pairs are left as-is to support WTF-8. All other invalid codes become replacement characters (fffd).

• src Array to encode.
• dst Output string prefix, default is empty.
• srcPos Initial offset to source data, default is 0.
• srcEnd Source data end offset, default is its length.

Returns decoded string.

License

The MIT License

Copyright (c) 2019- RequireX authors.