Which JS versions are supported?

ES2024+. Modern features (optional chaining, nullish coalescing, dynamic imports, top-level await) format correctly.

Separate mode. Toggle to JSX for React-style syntax. Without it, JSX throws parse errors because plain JS doesn't know about angle-bracket tokens.

Partial — types and annotations format but type-specific rules (consistent type imports, generic formatting) are better handled by Prettier or ESLint.

Similar core, different project (js-beautify). Pre-dates Prettier; still used by many editors as the default JS formatter. Prettier has broader adoption today.

JS Beautifier | DevTools Surf

DevTools Surf

Example: JS Beautifier

A worked example, rendered from real sample data. Sign in to run the tool on your own input.

Input

function fibonacci(n){if(n<=1)return n;return fibonacci(n-1)+fibonacci(n-2)}const result=fibonacci(10);console.log("Result:",result);

Output

function fibonacci(n) {
  if (n <= 1) return n;
  return fibonacci(n - 1) + fibonacci(n - 2)
}
const result = fibonacci(10);
console.log("Result:", result);

About JS Beautifier

Beautify and format JavaScript code. Part of the DevTools Surf developer suite. Browse more tools in the JavaScript collection.

Use Cases

Frontend devs reformatting minified third-party library code for debugging
Code reviewers standardizing JavaScript formatting before reviewing PRs
Legacy codebase maintainers cleaning up inconsistently formatted JS files
Students learning JavaScript by reading well-formatted code examples

Tips

Choose between Allman and K&R brace styles for your team standard
Set max line length to keep beautified code readable
Beautify minified vendor scripts to debug production issues

Fun Facts

Brendan Eich created the first version of JavaScript in just 10 days in May 1995 at Netscape Communications.
JSBeautifier.org, one of the first online JS formatting tools, launched around 2007 and popularized browser-based code formatting.
Prettier, the opinionated code formatter, was released by James Long in 2017 and now formats over 20 languages beyond JavaScript.

FAQ

Which JS versions are supported?: ES2024+. Modern features (optional chaining, nullish coalescing, dynamic imports, top-level await) format correctly.
Does it handle JSX?: Separate mode. Toggle to JSX for React-style syntax. Without it, JSX throws parse errors because plain JS doesn't know about angle-bracket tokens.
TypeScript support?: Partial — types and annotations format but type-specific rules (consistent type imports, generic formatting) are better handled by Prettier or ESLint.
Is this Prettier?: Similar core, different project (js-beautify). Pre-dates Prettier; still used by many editors as the default JS formatter. Prettier has broader adoption today.

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