JavaScript Code Formatter

Edit JavaScript and see formatted output update live in your browser.

Input JavaScript (with line numbers)

Formatted Output (with line numbers)

Syntax check: Uses the Acorn JavaScript parser to report precise line and column numbers and lets you click the error message to jump to the location. If the parser CDN cannot load, browser-based checking is used as a fallback and positions may be approximate. Privacy: Code is processed locally and is not uploaded. The formatter itself is lightweight; review complex template literals, regular expressions, and unusual syntax.