JavaScript Beautifier

How to Use JavaScript Beautifier

When to Use JavaScript Beautifier

JavaScript Beautifier Examples

function add(a,b){return a+b}const result=[1,2,3].map(n=>add(n,10));console.log(result);

function add(a, b) {
  return a + b;
}
const result = [1, 2, 3].map(n => add(n, 10));
console.log(result);

async function fetchUser(id){const r=await fetch(`/api/users/${id}`);if(!r.ok)throw new Error('Not found');return r.json()}

async function fetchUser(id) {
  const r = await fetch(`/api/users/${id}`);
  if (!r.ok) throw new Error('Not found');
  return r.json();
}

class Counter{constructor(start=0){this.count=start}increment(){this.count++}reset(){this.count=0}}

class Counter {
  constructor(start = 0) {
    this.count = start;
  }
  increment() {
    this.count++;
  }
  reset() {
    this.count = 0;
  }
}

Tips & Best Practices for JavaScript Beautifier

• 1.Use 2-space indent for production code (matches Prettier defaults and most popular style guides). Use 4-space for legacy codebases that already use it — consistency within a codebase matters more than picking the 'best' style.
• 2.Beautifying is purely cosmetic. To truly understand minified third-party code, you also need to mentally restore variable names. Look for context clues: a function called with two strings is probably string manipulation; a callback with (a, b) and returning a comparison is likely a sort comparator.
• 3.If beautified code still seems unreadable, source maps are the proper fix. Most modern build tools generate them, and DevTools can use them to display original source while the browser executes minified code. Check if the script you're viewing has a //# sourceMappingURL comment.
• 4.For TypeScript or JSX, this beautifier handles standard JavaScript well but may not handle every edge case of TS-specific syntax (generic type parameters, type guards, decorators). For those, use a TypeScript-aware formatter like Prettier directly in your editor.
• 5.When auditing scripts for security, beautify first and then look for dynamic code execution (eval, new Function), unusual network requests (especially to unfamiliar domains), document.cookie or localStorage access, MutationObserver patterns, and obfuscated string operations like Base64 decoding or character code manipulation.
• 6.Beautified code is roughly 2-3x larger than minified code. For large files (>100 KB minified), expect noticeable processing time and a larger output. For massive bundles (>1 MB), consider using a desktop tool or your browser's DevTools 'Pretty Print' feature instead.

Frequently Asked Questions