stdlib-js / string-utf16-to-utf8-array

Convert a UTF-16 encoded string to an array of integers using UTF-8 encoding.

About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

UTF-16 to UTF-8

Convert a UTF-16 encoded string to an array of integers using UTF-8 encoding.

Installation

npm install @stdlib/string-utf16-to-utf8-array

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var utf16ToUTF8Array = require( '@stdlib/string-utf16-to-utf8-array' );

utf16ToUTF8Array( str )

Converts a UTF-16 encoded string to an array of integers using UTF-8 encoding.

var out = utf16ToUTF8Array( '☃' );
// returns [ 226, 152, 131 ]

Notes

• UTF-16 encoding uses one 16-bit unit for non-surrogates (U+0000 to U+D7FF and U+E000 to U+FFFF).

• UTF-16 encoding uses two 16-bit units (surrogate pairs) for U+10000 to U+10FFFF and encodes U+10000-U+10FFFF by subtracting 0x10000 from the code point, expressing the result as a 20-bit binary, and splitting the 20 bits of 0x0-0xFFFFF as upper and lower 10-bits. The respective 10-bits are stored in two 16-bit words: a high and a low surrogate.

• UTF-8 is defined to encode code points in one to four bytes, depending on the number of significant bits in the numerical value of the code point. Encoding uses the following byte sequences:

  0x00000000 - 0x0000007F:
      0xxxxxxx
  
  0x00000080 - 0x000007FF:
      110xxxxx 10xxxxxx
  
  0x00000800 - 0x0000FFFF:
      1110xxxx 10xxxxxx 10xxxxxx
  
  0x00010000 - 0x001FFFFF:
      11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
  

  where an x represents a code point bit. Only the shortest possible multi-byte sequence which can represent a code point is used.

Examples

var utf16ToUTF8Array = require( '@stdlib/string-utf16-to-utf8-array' );

var values;
var out;
var i;

values = [
    'Ladies + Gentlemen',
    'An encoded string!',
    'Dogs, Cats & Mice',
    '☃',
    'æ',
    '𐐷'
];
for ( i = 0; i < values.length; i++ ) {
    out = utf16ToUTF8Array( values[ i ] );
    console.log( '%s: %s', values[ i ], out.join( ',' ) );
}

---

Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

---

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.