esprima

Esprima is a JavaScript parser written in JavaScript that analyzes JavaScript source code and produces an Abstract Syntax Tree. It implements the ECMAScript language specification and generates ESTree-compatible ASTs, providing location data such as line and column numbers and optional ranges.

In addition to parsing, Esprima offers options to control parsing behavior, including ecmaVersion (to select the ECMAScript edition to support), sourceType (script or module), and tolerance options to allow for some syntax variations. The parser can be used in both Node.js and browser environments and is accessible via npm as a module or via URL scripts.

Esprima is widely used by tooling in the JavaScript ecosystem. It has been employed by code analysis, linting, and transformation tools and is compatible with other AST consumer libraries. It is one of several standalone parsers used to generate ESTree-compatible trees alongside Acorn and Babel’s parser.

The project is open-source, and its repositories provide documentation, examples, and integration guides for common workflows. Developers use Esprima to convert source text into a structured representation that downstream tools can navigate for static analysis, refactoring, transpilation, and general code understanding.