Developer Tools
JavaScript Formatter Online
Beautify JavaScript for debugging, review and documentation. Source code is processed locally in your browser.
JavaScript formatting workspace
Process code locally, compare before/after size, then copy, download or continue working with the result.
Input
117 chars
1 line
Output
0 chars
0 lines
Size change
—
Compared after processing
Privacy
Local browser
Code is not uploaded
Formatting and minification are text transformations, not compilers or runtime validators. Test production output with the relevant browser, build tool or application runtime.
About JavaScript Formatter
JavaScript Formatter turns compact or poorly indented code into a readable layout for debugging, review and documentation. It helps expose block structure, callbacks, object literals and control flow. Formatting does not verify program correctness, resolve dependencies or safely reverse advanced obfuscation, so the output should be tested before use.
Key Features
How to Use
- Paste the JavaScript source into the input editor.
- Run the formatter and review the block structure.
- Check strings, regular expressions, template literals and modern syntax.
- Test the formatted code in a safe development environment before deployment.
Practical Example
Input
const total=(items)=>items.reduce((sum,item)=>sum+item.price,0);
Output
const total = (items) => items.reduce((sum, item) => sum + item.price, 0);
Popular Use Cases
Best Practices
- ✓ Run automated tests after formatting important code.
- ✓ Use a parser, linter and project formatter in production repositories.
- ✓ Review third-party code before executing it.
- ✓ Keep source maps and original source files when debugging bundles.
Common Mistakes
- • Executing unknown formatted code simply because it looks readable.
- • Assuming formatting removes malicious behaviour.
- • Treating beautification as syntax validation.
- • Replacing source-controlled files without reviewing the diff.
Privacy and Processing
JavaScript is processed locally in your browser during normal use. Avoid executing untrusted output; formatting and execution are separate activities.
Important limitation: The formatter does not deobfuscate every bundle, restore original variable names, resolve modules or guarantee support for every experimental syntax feature.
Frequently Asked Questions
Can a formatter restore original source code?
No. It can improve indentation, but it cannot recover original names, comments or architecture removed during bundling or minification.
Does formatting validate JavaScript?
No. Use a parser, linter and tests to validate syntax and behaviour.
Is it safe to run formatted third-party code?
Formatting does not make unknown code safe. Review it and use an isolated environment before execution.
Can it format modern JavaScript?
Common modern syntax is supported, but experimental or tool-specific syntax may require the formatter used by your project.
Can I minify it again?
Yes. Use the JavaScript Minifier after testing the readable source.
Is source code uploaded?
No. Normal formatting occurs locally in the browser.