RegExp Tree: Regular Expression Processor

regexp-tree is a JavaScript library designed for comprehensive processing of regular expressions. It provides a full suite of APIs including a parser that generates an Abstract Syntax Tree (AST) based on the ECMAScript regular expression grammar, tools for AST traversal and transformation, an optimizer, and an interpreter. It also features a compatibility transpiler and supports custom regular expression extensions. Currently stable at version 0.1.27, it appears to be actively maintained, though release cadence isn't explicitly stated. Its key differentiators include its extensive set of processing capabilities beyond simple parsing, offering deep inspection, modification, and optimization of regular expressions. The library also ships with TypeScript type definitions, enhancing developer experience for TypeScript users.