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fast-levenshtein - Levenshtein algorithm in Javascript

An efficient Javascript implementation of the Levenshtein algorithm with asynchronous callback 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).
Provides synchronous and asynchronous versions of the algorithm.
Asynchronous version is almost as fast as the synchronous version for small strings and can also provide progress updates.
Comprehensive test suite and performance benchmark.
Small: <1 KB minified and gzipped

Installation

node.js

Install using npm:

$ npm install fast-levenshtein

Browser

Using bower:

$ 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

Synchronous

var levenshtein = require('fast-levenshtein');

var distance = levenshtein.get('back', 'book');   // 2
var distance = levenshtein.get('我愛你', '我叫你');   // 1

Asynchronous

var levenshtein = require('fast-levenshtein');

levenshtein.getAsync('back', 'book', function (err, distance) {
  // err is null unless an error was thrown
  // distance equals 2
});

Asynchronous with progress updates

var levenshtein = require('fast-levenshtein');

var hugeText1 = fs.readFileSync(...);
var hugeText2 = fs.readFileSync(...);

levenshtein.getAsync(hugeText1, hugeText2, function (err, distance) {
  // process the results as normal
}, {
  progress: function(percentComplete) {
    console.log(percentComplete + ' % completed so far...');
  }
);

Building and Testing

To build the code and run the tests:

$ npm install -g grunt-cli
$ npm install
$ npm run build

Performance

Thanks to Titus Wormer for encouraging me to do this.

Benchmarked against other node.js levenshtein distance modules (on Macbook Air 2012, Core i7, 8GB RAM):

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:

$ npm install -g grunt-cli
$ 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 for details.

License

MIT - see LICENSE.md

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