# fast-levenshtein - Levenshtein algorithm in Javascript
[](http://travis-ci.org/hiddentao/fast-levenshtein)
[](https://badge.fury.io/js/fast-levenshtein)
[](https://www.npmjs.com/package/fast-levenshtein)
[](https://twitter.com/hiddentao)
An efficient Javascript implementation of the [Levenshtein algorithm ](http://en.wikipedia.org/wiki/Levenshtein_distance ) with locale-specific collator support.
## Features
* Works in node.js and in the browser.
* Better performance than other implementations by not needing to store the whole matrix ([more info](http://www.codeproject.com/Articles/13525/Fast-memory-efficient-Levenshtein-algorithm)).
* Locale-sensitive string comparisions if needed.
* Comprehensive test suite and performance benchmark.
* Small: < 1 KB minified and gzipped
## Installation
### node.js
Install using [npm ](http://npmjs.org/ ):
```bash
$ npm install fast-levenshtein
```
### Browser
Using bower:
```bash
$ bower install fast-levenshtein
```
If you are not using any module loader system then the API will then be accessible via the `window.Levenshtein` object.
## Examples
**Default usage**
```javascript
var levenshtein = require('fast-levenshtein');
var distance = levenshtein.get('back', 'book'); // 2
var distance = levenshtein.get('我愛你', '我叫你'); // 1
```
**Locale-sensitive string comparisons**
It supports using [Intl.Collator ](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Collator ) for locale-sensitive string comparisons:
```javascript
var levenshtein = require('fast-levenshtein');
levenshtein.get('mikailovitch', 'Mikhaïlovitch', { useCollator: true});
// 1
```
## Building and Testing
To build the code and run the tests:
```bash
$ npm install -g grunt-cli
$ npm install
$ npm run build
```
## Performance
_Thanks to [Titus Wormer ](https://github.com/wooorm ) for [encouraging me ](https://github.com/hiddentao/fast-levenshtein/issues/1 ) to do this._
Benchmarked against other node.js levenshtein distance modules (on Macbook Air 2012, Core i7, 8GB RAM):
```bash
Running suite Implementation comparison [benchmark/speed.js]...
>> levenshtein-edit-distance x 234 ops/sec ±3.02% (73 runs sampled)
>> levenshtein-component x 422 ops/sec ±4.38% (83 runs sampled)
>> levenshtein-deltas x 283 ops/sec ±3.83% (78 runs sampled)
>> natural x 255 ops/sec ±0.76% (88 runs sampled)
>> levenshtein x 180 ops/sec ±3.55% (86 runs sampled)
>> fast-levenshtein x 1,792 ops/sec ±2.72% (95 runs sampled)
Benchmark done.
Fastest test is fast-levenshtein at 4.2x faster than levenshtein-component
```
You can run this benchmark yourself by doing:
```bash
$ npm install
$ npm run build
$ npm run benchmark
```
## Contributing
If you wish to submit a pull request please update and/or create new tests for any changes you make and ensure the grunt build passes.
See [CONTRIBUTING.md ](https://github.com/hiddentao/fast-levenshtein/blob/master/CONTRIBUTING.md ) for details.
## License
MIT - see [LICENSE.md ](https://github.com/hiddentao/fast-levenshtein/blob/master/LICENSE.md )
