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JavaScript Beautifier

Beautify JavaScript snippets with indentation and spacing normalization.

About JavaScript Beautifier

Minified JavaScript is designed to be executed by machines, not read by humans. When you need to understand what a third-party script does, debug a production bundle, audit an npm package's actual code, or recover a readable version from a concatenated build artifact, you need a JavaScript beautifier. This tool takes any minified, concatenated, or poorly formatted JavaScript and reformats it into clean, properly indented code with consistent spacing, line breaks after statements, and block structure you can navigate. It handles ES5, ES6+, arrow functions, template literals, destructuring, async/await, and class syntax. Paste code from a minified bundle, a browser script tag, DevTools Sources panel, or a production CDN file and get a readable version immediately — all processing runs in your browser with no server upload.

Why use JavaScript Beautifier

Reads Any Modern JS Syntax

Correctly formats ES2015+ features including arrow functions, destructuring, template literals, optional chaining, nullish coalescing, and async/await.

Third-Party Script Auditing

Unminify any script tag, analytics snippet, or npm package output to audit what code is actually running on your page before trusting it.

Configurable Code Style

Match your team's style guide by choosing indentation width and quote preference — reduces friction when pasting beautified code into an existing codebase.

Production Bundle Debugging

Unminify a specific bundle chunk to locate a bug in production when source maps are unavailable, without needing to rebuild the entire project.

Preserves Logic and Structure

Beautification only modifies whitespace — it never reorders statements, renames variables, or changes the logic of the original code.

No Install or Build Step

Available instantly in the browser without npm install, Prettier config, or editor plugins — useful on any machine, including read-only or restricted environments.

How to use JavaScript Beautifier

  1. Paste your minified or concatenated JavaScript into the input panel.
  2. The beautified code appears in the output panel instantly — results update as you type.
  3. Select your preferred indentation style: 2 spaces, 4 spaces, or tabs.
  4. Toggle semicolons and quote style (single vs. double) to match your team's coding standard.
  5. Click Copy to copy the formatted JavaScript to your clipboard.
  6. Paste the result into your code editor, a gist, or a code review tool for further analysis.

When to use JavaScript Beautifier

  • When debugging a production JavaScript error and the stack trace points to a minified bundle that cannot be read without formatting.
  • When auditing a third-party tag manager script, analytics snippet, or ad network JavaScript to verify it does not contain unexpected behavior.
  • When reviewing code in a pull request where a minified build artifact was accidentally committed alongside source changes.
  • When inspecting the output of a bundler (Webpack, Rollup, Vite) to understand how your modules were combined and tree-shaken.
  • When working on a machine without your usual editor or Prettier setup and needing to quickly format a script before reading it.
  • When extracting and reading inline JavaScript from an HTML page's script tags that were minified by a site generator or CMS.

Examples

Minified function

Input: function add(a,b){return a+b;}const result=add(3,4);console.log(result);

Output: function add(a, b) { return a + b; } const result = add(3, 4); console.log(result);

Minified arrow function and destructuring

Input: const greet=({name,age})=>`Hello ${name}, you are ${age} years old.`;const users=[{name:'Alice',age:30},{name:'Bob',age:25}];users.forEach(u=>console.log(greet(u)));

Output: const greet = ({ name, age }) => `Hello ${name}, you are ${age} years old.`; const users = [ { name: 'Alice', age: 30 }, { name: 'Bob', age: 25 } ]; users.forEach(u => console.log(greet(u)));

Minified async/await fetch

Input: async function fetchUser(id){try{const res=await fetch(`/api/users/${id}`);if(!res.ok)throw new Error('Not found');return await res.json();}catch(e){console.error(e);return null;}}

Output: async function fetchUser(id) { try { const res = await fetch(`/api/users/${id}`); if (!res.ok) throw new Error('Not found'); return await res.json(); } catch (e) { console.error(e); return null; } }

Tips

  • After beautifying, use Ctrl+F to search for specific function names or strings — formatted code makes keyword search far more useful than scanning minified output.
  • Copy only the specific IIFE or module chunk you are investigating rather than the entire bundle — the tool handles any valid JavaScript fragment.
  • Look for console.log statements in beautified third-party scripts — they are often left in minified code and reveal implementation details about what the script tracks.
  • Use the 2-space output mode when preparing beautified code to show in documentation or a blog post — it is more compact and easier to read in narrow columns.
  • Beautify → copy → paste into a temporary editor file and use multi-cursor or find-replace to trace a specific variable name through the logic.

Frequently Asked Questions

Does the JavaScript beautifier change the behavior of my code?▾
No. Beautification only adds whitespace — line breaks, spaces, and indentation. It does not rename variables, reorder statements, or modify any logic. The beautified output is semantically identical to the minified input.
Can it handle TypeScript or JSX?▾
The tool is designed for standard JavaScript. TypeScript (type annotations, interfaces, generics) and JSX may partially format but contain syntax the parser does not fully understand. For TypeScript and JSX formatting, use Prettier with the appropriate parser in your editor.
What is the difference between beautifying and deobfuscating JavaScript?▾
Beautification restores readable formatting (whitespace and indentation) but cannot reverse obfuscation techniques like variable renaming (a, b, c), string encoding, or control-flow flattening. For obfuscated code, beautification is the first step — readable structure makes manual analysis easier, but fully reversing obfuscation requires dedicated deobfuscation tools.
Can I beautify JavaScript modules with import and export statements?▾
Yes. ES module syntax including named exports, default exports, re-exports, and dynamic import() expressions are all supported and formatted correctly.
Does it support class syntax and private fields?▾
Yes. ES2015 class declarations, class expressions, extends, static methods, and ES2022 private fields (#field) are handled by the formatter.
Is there a file size limit?▾
There is no enforced size limit. Very large bundles (1MB+) may take a second to process as all parsing and formatting runs in your browser's JavaScript engine.
How does this compare to running Prettier locally?▾
Prettier is the industry standard and enforces a strict opinionated style. This tool is designed for quick read-only access — pasting a snippet you want to read, not formatting source files in a project. For project-wide formatting, Prettier with an .editorconfig or .prettierrc is the right choice.
Can I use it to recover readable code from a bundled library?▾
Yes, with limitations. Bundlers rename modules and may merge multiple files, so beautified output may have single-letter variable names and no module boundaries. Beautification restores the block structure and spacing, making the logic navigable, but module-level context is lost unless source maps are available.

Explore the category

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Glossary

Minification
The automated process of removing whitespace, comments, and shortening variable names in JavaScript to reduce file size for faster browser download. Produces code that executes identically but is unreadable.
Beautification (Pretty-Printing)
The reverse of minification — reformatting code with consistent indentation, line breaks, and spacing to make it human-readable. Also called code formatting or pretty-printing.
Obfuscation
A more aggressive transformation than minification that renames variables to meaningless names and encodes strings to make reverse-engineering difficult. Beautification cannot undo obfuscation.
AST (Abstract Syntax Tree)
A tree representation of the syntactic structure of source code. JavaScript beautifiers parse code into an AST and then re-serialize it with formatting applied.
IIFE (Immediately Invoked Function Expression)
A JavaScript pattern where a function is defined and immediately called: (function() { ... })(). Commonly used in bundler output to create isolated scopes.
Source Map
A file (.map) that maps minified/bundled output back to the original source files with original variable names and line numbers. Source maps make DevTools debugging of production bundles possible without a beautifier.