A tool set for CSS: fast detailed parser (CSS → AST), walker (AST traversal), generator (AST → CSS) and lexer (validation and matching) based on specs and browser implementations
Query JavaScript objects with JSONPath expressions. Robust / safe JSONPath engine for Node.js.
Walk any kind of tree structure depth- or breadth-first. Supports promises and advanced map-reduce operations with a very small API.
Execute a callback on every node of a source code's AST and stop walking when you see fit