eslint
An AST-based pattern checker for JavaScript.
espree
An Esprima-compatible JavaScript parser built on Acorn
esquery
A query library for ECMAScript AST using a CSS selector like query language.
css-tree
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