121 lines
3.4 KiB
Markdown
121 lines
3.4 KiB
Markdown
# fast-levenshtein - Levenshtein algorithm in Javascript
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[](http://travis-ci.org/hiddentao/fast-levenshtein)
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An efficient Javascript implementation of the [Levenshtein algorithm](http://en.wikipedia.org/wiki/Levenshtein_distance) with asynchronous callback support.
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## Features
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* Works in node.js and in the browser.
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* 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)).
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* Provides synchronous and asynchronous versions of the algorithm.
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* Asynchronous version is almost as fast as the synchronous version for small strings and can also provide progress updates.
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* Comprehensive test suite and performance benchmark.
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* Small: <1 KB minified and gzipped
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## Installation
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### node.js
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Install using [npm](http://npmjs.org/):
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```bash
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$ npm install fast-levenshtein
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```
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### Browser
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Using bower:
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```bash
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$ bower install fast-levenshtein
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```
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If you are not using any module loader system then the API will then be accessible via the `window.Levenshtein` object.
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## Examples
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**Synchronous**
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```javascript
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var levenshtein = require('fast-levenshtein');
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var distance = levenshtein.get('back', 'book'); // 2
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var distance = levenshtein.get('我愛你', '我叫你'); // 1
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```
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**Asynchronous**
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```javascript
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var levenshtein = require('fast-levenshtein');
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levenshtein.getAsync('back', 'book', function (err, distance) {
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// err is null unless an error was thrown
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// distance equals 2
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});
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```
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**Asynchronous with progress updates**
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```javascript
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var levenshtein = require('fast-levenshtein');
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var hugeText1 = fs.readFileSync(...);
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var hugeText2 = fs.readFileSync(...);
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levenshtein.getAsync(hugeText1, hugeText2, function (err, distance) {
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// process the results as normal
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}, {
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progress: function(percentComplete) {
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console.log(percentComplete + ' % completed so far...');
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}
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);
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```
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## Building and Testing
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To build the code and run the tests:
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```bash
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$ npm install -g grunt-cli
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$ npm install
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$ npm run build
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```
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## Performance
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_Thanks to [Titus Wormer](https://github.com/wooorm) for [encouraging me](https://github.com/hiddentao/fast-levenshtein/issues/1) to do this._
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Benchmarked against other node.js levenshtein distance modules (on Macbook Air 2012, Core i7, 8GB RAM):
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```bash
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Running suite Implementation comparison [benchmark/speed.js]...
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>> levenshtein-edit-distance x 234 ops/sec ±3.02% (73 runs sampled)
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>> levenshtein-component x 422 ops/sec ±4.38% (83 runs sampled)
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>> levenshtein-deltas x 283 ops/sec ±3.83% (78 runs sampled)
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>> natural x 255 ops/sec ±0.76% (88 runs sampled)
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>> levenshtein x 180 ops/sec ±3.55% (86 runs sampled)
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>> fast-levenshtein x 1,792 ops/sec ±2.72% (95 runs sampled)
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Benchmark done.
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Fastest test is fast-levenshtein at 4.2x faster than levenshtein-component
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```
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You can run this benchmark yourself by doing:
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```bash
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$ npm install -g grunt-cli
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$ npm install
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$ npm run build
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$ npm run benchmark
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```
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## Contributing
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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.
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See [CONTRIBUTING.md](https://github.com/hiddentao/fast-levenshtein/blob/master/CONTRIBUTING.md) for details.
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## License
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MIT - see [LICENSE.md](https://github.com/hiddentao/fast-levenshtein/blob/master/LICENSE.md)
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