• Take advantage of Oniguruma's many extended regex features in JavaScript.
• Run regexes written for Oniguruma from JavaScript, such as those used in TextMate grammars (used by VS Code, Shiki syntax highlighter, etc.).
• Share regexes across your Ruby and JavaScript code.^︎

Oniguruma-To-ES deeply understands the hundreds of large and small differences between Oniguruma and JavaScript regex syntax and behavior, across multiple JavaScript version targets. It's obsessive about ensuring that the emulated features it supports have exactly the same behavior, even in extreme edge cases. And it's been battle-tested on thousands of real-world Oniguruma regexes used in TextMate grammars (via the Shiki library).

Depending on features used, Oniguruma-To-ES might use advanced emulation via a RegExp subclass (that remains a native JavaScript regular expression).

There's also a demo page. Check it out!

^{︎: Ruby 2.0+ uses Onigmo, a fork of Oniguruma with similar syntax and behavior.}

Check it out: Regexes Got Good: The History And Future Of Regular Expressions In JavaScript.

Regex+

Regex+ provides a regex template tag for dynamically creating readable, high performance, native JavaScript regular expressions with best practices built-in and powerful/advanced features that improve performance, readability, and maintainability. It's lightweight and supports all ES2025 regex features.

Highlights include support for free-spacing and comments, atomic groups and possessive quantifiers (that can help you avoid ReDoS), subroutines and subroutine definition groups (that enable powerful subpattern composition), and context-aware interpolation of RegExp instances, escaped strings, and partial patterns.

Run npm install regex in your JavaScript project and then simply import {regex} from 'regex' to get started. Check out examples and more on GitHub.

Regex Colorizer 1.0

Regex Colorizer is a project that highlights regex syntax, for use in blogs, docs, and regex tools. I created it for old-school RegexPal back in 2007, but it hadn't received any updates since 2010. Until now. Version 1.0 is a significant update that improves its API and adds support for modern JavaScript regex syntax and flags. Check out the demo!

I created a curated list on GitHub of the best regular expression tools, tutorials, libraries, and many other resources. It covers all major regex flavors, and currently includes especially deep coverage of regular expressions in JavaScript (including a concise history of all regex features added to JavaScript in ES6 through ES2024, plus active proposals for the future).

Check it out, and return to it easily with a handy shortcut URL: regex.cool.

• parseUri gives you many additional properties (authority, userinfo, subdomain, domain, tld, resource, directory, filename, suffix) that are not available from URL.
• URL throws e.g. if not given a protocol, and in many other cases of valid (but not supported) and invalid URIs. parseUri makes a best case effort even with partial or invalid URIs and is extremely good with edge cases.
• URL’s rules don’t allow correctly handling many non-web protocols. For example, URL doesn’t throw on any of 'git://localhost:1234', 'ssh://myid@192.168.1.101', or 't2ab:///path/entry', but it also doesn’t get their details correct since it treats everything after : up to ? or # as part of the pathname.
• parseUri includes a “friendly” parsing mode (in addition to its default mode) that handles human-friendly URLs like 'example.com/index.html' as expected.
• parseUri includes partial/extensible support for second-level domains like in '//example.co.uk'.

Conversely, parseUri is single-purpose and doesn’t do normalization. But of course you can pass URIs through a normalizer separately, if you need that. Or, if you wanted to create an exceptionally lightweight URI normalizer, parseUri would be a great base to build on top of.

So although it’s needed less often these days because of the built-in URL, if URL is ever not enough for your needs, this is an extremely accurate, flexible, and lightweight option.

Check it out!

• parseUri on GitHub
• The demo page lets you easily test and compare results
• Changelog
• Tests
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