JavaScript AST Explorer

How to use JavaScript AST Explorer

Inspect syntax-node types and source ranges in a JavaScript script or module. Acorn parses an explicit ECMAScript2022 grammar and an iterative walk emits indexed node paths, types and original start/end offsets. The report shows structure without evaluating expressions or loading imports.

1. Provide javascript source.
2. Choose the supported mode and run the tool. Review its assumptions and any reported errors.
3. Copy the result or download a separate output; reset to clear the current form.

Good to know

• 50,000 source characters;10 seconds to load the worker/libraries, then2 seconds to compute. The worker is terminated on success, failure or timeout.
• Output is untrusted source text: it is never executed or inserted into this page. No linked resources or source maps are fetched.
• At most30,000 nodes and100 nesting levels; reports can hit the500,000-character output cap sooner. This is syntax inspection, not type checking, linting or a security verdict.
• Inputs are processed on this device and are not automatically saved or uploaded.