Google Closure Compiler and JSDoc Type Expression Parser

Catharsis is a JavaScript library designed for parsing and manipulating type expressions used by Google Closure Compiler and JSDoc. It provides robust capabilities to convert these expressions into a structured Abstract Syntax Tree (AST), and then back into a string or a human-readable description. The current stable version is 0.11.0, last published about a year ago, indicating an irregular or maintenance-focused release cadence. Key differentiators include its high accuracy, backed by a Peggy grammar and a comprehensive test suite, and its flexibility in handling both standard Closure Compiler syntax and JSDoc-specific extensions like `string[]` for `Array<string>`. This library is primarily used by tools and systems that need to interpret or generate type annotations, offering programmatic access to the structure and meaning of complex type expressions.