ts-levenshtein

ts-levenshtein - Levenshtein algorithm in TypeScript

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A TypeScript implementation of the Levenshtein algorithm with locale-specific collator support. The core is an internal Myers bit‑parallel implementation (no external runtime dependency), with small‑string DP fast path and typed‑array buffer reuse.

Features

• Works in node.js and in the browser.
• Locale-sensitive string comparisons if needed.
• Comprehensive test suite.

Installation

npm install ts-levenshtein

CDN

You can load either the global IIFE build or ESM via esm.sh.

• IIFE (global TSLevenshtein):
  • jsDelivr: https://cdn.jsdelivr.net/npm/ts-levenshtein/dist/index.global.js
  • unpkg: https://unpkg.com/ts-levenshtein/dist/index.global.js
• ESM (esm.sh):
  • https://esm.sh/ts-levenshtein

Examples

Default usage (Node.js)

// CommonJS (npm)
const levenshtein = require("ts-levenshtein").default;
console.log(levenshtein.get("back", "book")); // 2
console.log(levenshtein.get("我愛你", "我叫你")); // 1

// or ESM
// import levenshtein from 'ts-levenshtein'
// console.log(levenshtein.get('back', 'book'))

Browser via CDN (IIFE)

<script src="https://cdn.jsdelivr.net/npm/ts-levenshtein/dist/index.global.js"></script>
<script>
  // Global name: TSLevenshtein
  const d1 = TSLevenshtein.default.get('kitten', 'sitting');
  const d2 = TSLevenshtein.default.get('我愛你', '我叫你');
  console.log(d1, d2);
  // If you prefer unpkg:
  // <script src="https://unpkg.com/ts-levenshtein/dist/index.global.js"></script>
  // Note: CDN availability depends on publishing to npmjs.

  // Optional: ESM via CDN loaders may vary by toolchain.
</script>

Browser via CDN (ESM with esm.sh)

<script type="module">
  import levenshtein from 'https://esm.sh/ts-levenshtein?bundle';
  console.log(levenshtein.get('kitten', 'sitting'));
  console.log(levenshtein.get('我愛你', '我叫你'));
  // Tip: `?bundle` helps ensure a single file for browsers
  // Deno: import levenshtein from 'https://esm.sh/ts-levenshtein'
</script>

Locale-sensitive string comparisons

It supports using Intl.Collator for locale-sensitive string comparisons:

// CommonJS (npm)
const levenshtein = require("ts-levenshtein").default;
levenshtein.get("mikailovitch", "Mikhaïlovitch", { useCollator: true });
// 1

// or ESM
// import levenshtein from 'ts-levenshtein'
// levenshtein.get('mikailovitch', 'Mikhaïlovitch', { useCollator: true })

Module formats and tooling

• CJS: dist/index.cjs
• ESM: dist/index.mjs
• UMD: dist/index.umd.js
• IIFE (global): dist/index.global.js (global TSLevenshtein)
• TypeScript types: dist/index.d.ts (exposed via "types" field)
• Source maps: available for all builds

Building and Testing

To build the code and run the tests:

npm install
npm run build
npm test

Performance

Internals:

• Myers bit‑parallel algorithm for the non‑collator path (≤32 uses 32‑bit variant, longer strings use blocked variant)
• Small‑string (≤20) classic DP fast path
• Common prefix/suffix trimming
• Typed arrays (Uint16Array/Int32Array) and fixed‑capacity buffer reuse to minimize allocations

Run the included benchmark:

npm run benchmark

Results vary by machine/Node version; expect competitive performance while keeping correctness and zero external deps.

Benchmark

Sample run (lower is faster):

Environment: Apple M4 MacBook, Node.js 22

Rank	Implementation	Time (ms)	Relative to fastest	Status
1	ts-levenshtein	0.71	0.00%	ok
2	levenshtein-edit-distance	1.82	156.34%	ok
3	levenshtein	2.57	261.97%	ok
4	levenshtein-component	3.18	347.89%	ok
5	levenshtein-deltas	4.04	469.01%	ok
6	natural	14.41	1929.58%	ok

Contributing

If you wish to submit a pull request, please update and/or create new tests for any changes you make and ensure the build and tests pass locally (npm run build, npm test).

See CONTRIBUTING.md for details.

License

MIT - see LICENSE.md

Changelog

1.0.7 (2025-08-15)

Features

• add Arabic and Chinese translations to README and examples; enhance online demo with multilingual support (c63035d)