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Beautified JavaScript
About This Tool
This tool formats or compresses JavaScript code. Beautify mode adds proper indentation, line breaks, and spacing so you can read and debug minified bundles. Minify mode strips whitespace, comments, and unnecessary characters to reduce file size. The validator catches common syntax errors—unmatched braces, brackets, or parentheses—before they cause runtime failures. You can enforce quote style consistency and control semicolon insertion. Everything runs in your browser, no code leaves your machine.
How to Use
- Paste your JavaScript or upload a .js file
- Pick Beautify to format with indentation, or Minify to compress
- Adjust settings: indent size, quote style (single/double/preserve), semicolon handling
- Output updates automatically as you type or change settings
- Copy the result or download as a file
Common Use Cases
- Debugging production bundles: Got a minified error stack? Beautify the source to find the actual line causing issues
- Code review: Format JavaScript consistently so diffs show logic changes, not formatting differences
- Learning from libraries: Beautify minified jQuery or React builds to understand how they work
- Quick optimization: Need to shrink a script by 30-40% before embedding? Minify it
- Quote normalization: Enforce single or double quotes across a codebase for linting consistency
Limitations
- This is a lightweight formatter, not a full JavaScript parser—it won't catch semantic errors or perform advanced transformations like tree-shaking
- The validator detects bracket mismatches but won't identify logical bugs or type errors
- Very large files (5MB+) may slow down your browser—use build tools like Webpack or esbuild for production bundles
- String content with bracket characters may cause false-positive validation warnings
- ES6+ syntax (template literals, destructuring) is supported but edge cases may not format perfectly
- For production use, pair this with source maps to debug minified code