rregex

A dependency-free WebAssembly build of Rust Regex for Javascript

• Why Rust Regex
• Install
• Supported Runtimes
• API
  • RRegex
  • RRegexSet
  • Match
  • Captures
  • escape
• Benchmarks
• Known Issues

Why Rust Regex

Rust has a powerful Regex library with a lot of features that don't exists en the standard Regex object

See the official documentation for more detail

Install

  # NPM
  npm install rregex

  # Yarn
  yarn add rregex

  # PNPM
  pnpm add rregex

  # Deno
  deno add @rregex/rregex

  # JSR
  npx jsr add @rregex/rregex

Supported Runtimes

This package includes builds for multiple runtimes

Runtime	Import	version
Node.js (esm)	import { RRegex, RRegexSet } from 'rregex'	*
Node.js (commonjs)	const { RRegex, RRegexSet } = require('rregex')	*
Deno	import { RRegex, RRegexSet } from '@rregex/rregex'	>=1.10.8
Bun	import { RRegex, RRegexSet } from '@rregex/rregex'	>=1.10.8
Cloudflare Workers	import { RRegex, RRegexSet } from 'rregex/lib/cf.mjs'	>=1.10.8
Browser	TODO
Standalone	TODO

Benchmarks

In general terms rregex is at least 1 order of magnitud slower than the native RegExp object, but still have a good performance. Unless you required some of the features that rregex provides, you should always consider using the native RegExp object

Benchmarks are executed using test/deno.bench.mjs, and test/node.bench.mjs

Email

benchmark	time (avg)	iter/s
RegExp	254.8 µs/iter	3,925.0
RRegex	1.7 ms/iter	589.9

summary: RegExp is 6.65x faster than RRegex

IP

benchmark	time (avg)	iter/s
RegExp	39.1 µs/iter	25,600.0
RRegex	1.4 ms/iter	698.1

summary: RegExp is 36.67x faster than RRegex

URI

benchmark	time (avg)	iter/s
RegExp	422.7 ns/iter	2,366,000.0
RRegex	1.5 ms/iter	652.6

summary: RegExp is 3625x faster than RRegex

benckmarks	benckmarks

Note: In order to compare with native regex these benchmarks follow the mariomka/regex-benchmark structure

Known Issues

If you call splitn(text, limit) and the expected result length is equal to limit - 1 the result will include an extra item "", this behavior does not happen if limit es greater. fixed at >=1.3

const regex = new RRegex(",");
expect(regex.splitn("a,b,c", 0)).toEqual([]);
expect(regex.splitn("a,b,c", 1)).toEqual(["a,b,c"]);
expect(regex.splitn("a,b,c", 2)).toEqual(["a", "b,c"]);
expect(regex.splitn("a,b,c", 3)).toEqual(["a", "b", "c"]);

// This result includes an unexpected extra item
expect(regex.splitn("a,b,c", 4)).toEqual(["a", "b", "c", ""]);
expect(regex.splitn("a,b,c", 5)).toEqual(["a", "b", "c"]);

expect(regex.splitn("abc", 0)).toEqual([]);
expect(regex.splitn("abc", 1)).toEqual(["abc"]);

// This result includes an unexpected extra item
expect(regex.splitn("abc", 2)).toEqual(["abc", ""]);
expect(regex.splitn("abc", 3)).toEqual(["abc"]);