What is a JavaScript formatter?
A JavaScript formatter (beautifier) takes minified or obfuscated JavaScript and reformats it with consistent indentation, spacing, and line breaks so the logic is readable. This is essential when debugging a minified library, reading a compiled bundle, or cleaning up auto-generated code. The minifier does the reverse — it strips comments and collapses whitespace — though it is not as aggressive as dedicated tools like Terser or UglifyJS. This tool uses the well-maintained js-beautify library loaded from the jsDelivr CDN.
How to use this tool
- 1 Paste your JavaScript into the Input panel.
- 2 Choose Prettify to reformat with indentation, or Minify to strip whitespace and comments.
- 3 Adjust the indent width to match your project style (default 2 spaces).
- 4 Copy the result with the copy button in the output panel header.
Frequently asked questions
Does this tool un-minify fully optimised production bundles?
Yes for whitespace and basic structure, but not for variable name mangling (e.g. a single-letter variable renamed from userSessionToken). For full deobfuscation you need a dedicated deobfuscator. js-beautify restores readability of the structure but can't recover original names.
Is the minifier as good as Terser or Babel?
No. The built-in minifier here only removes comments and collapses whitespace — it does not perform tree-shaking, dead-code elimination, or identifier mangling. Use Terser for production minification.
Is my code uploaded to a server?
No. js-beautify runs entirely in your browser. Formatting and minification happen locally; no code is transmitted.
Does it handle modern JavaScript (ES2022+, TypeScript)?
js-beautify handles most modern JavaScript syntax including arrow functions, destructuring, template literals, optional chaining, and nullish coalescing. TypeScript type annotations may cause some formatting oddities but the library handles many TS constructs.
Why does loading take a moment the first time?
The js-beautify library (~75 KB) is loaded from the jsDelivr CDN on first use and cached by the browser. Subsequent visits or tab refreshes use the browser cache instantly.