Category: Regular Expressions

A couple months ago I launched a new open source project, Oniguruma-To-ES. You can use it to:

• 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.}

I've recently released two new open source regex libraries.

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!