https://github.com/lautis/unicode-substring

Unicode-aware substring for JavaScript
https://github.com/lautis/unicode-substring

Last synced: 21 days ago
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Unicode-aware substring for JavaScript

• Host: GitHub
• URL: https://github.com/lautis/unicode-substring
• Owner: lautis
• License: mit
• Created: 2015-01-28T20:25:19.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2017-07-11T18:41:19.000Z (over 7 years ago)
• Last Synced: 2024-09-18T02:58:13.085Z (2 months ago)
• Language: JavaScript
• Size: 8.79 KB
• Stars: 23
• Watchers: 2
• Forks: 2
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# unicode-substring [![Build Status](https://travis-ci.org/lautis/unicode-substring.svg?branch=master)](https://travis-ci.org/lautis/unicode-substring)

Unicode-aware substring for JavaScript. Surrogate pairs are counted as a single character.

## What?

Characters in JavaScript strings are exposed as 16-bit code points, also known as UCS-2 encoding. This usually good enough, but since there are more than 2^16 characters in Unicode, 16 bits is not enough to represent all characters. To overcome this limitation, characters with scalar value over `0x10FFFF` need to be encoded as surrogate pairs. This encoding is known as UTF-16.

The purpose of this library is to treat surrogate pairs as one character when extracting substrings from a string. This might be preferable if indices are returned from an Unicode-compatible environment.

## Usage

```javascript

var unicodeSubstring = require('unicode-substring')

// unicodeSubstring(string, start, end)

unicodeSubstring("💥Emoji Rule💥", 0, 6)

// => "💥Emoji"

```

The `start` and `end` parameters behave similarly as [String.prototype.substring](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/String/substring).