Acorn JavaScript Parser

Acorn is a compact, high-performance JavaScript parser implemented entirely in JavaScript. It parses ECMAScript code into an Abstract Syntax Tree (AST) that conforms to the ESTree specification. The current stable version is 8.16.0, as of February 2026, with frequent releases to support the latest ECMAScript features and bug fixes. Acorn differentiates itself by its minimal footprint and speed, serving as a fundamental component in many JavaScript tooling projects, including linters (like ESLint), bundlers, and transpilers. It strictly implements 'stage 4' (finalized) ECMAScript features, requiring plugins for experimental syntax.