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JavaScript Minifier / Beautifier

Minify JavaScript code to reduce file size or beautify compressed scripts into clean, readable code with syntax highlighting. Format, compress, and optimize JS instantly.

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Input 33 lines · 531 chars

Formatted 1 lines · 0 chars

// Fibonacci sequence

function fibonacci(n) {

 if (n  <=  1) return n;

 let a  =  0, b  =  1, temp;

 for (let i  =  2;
 i  <=  n;
 i ++ ) {

 temp  =  a  +  b;

 a  =  b;

 b  =  temp;
  }

 return b;
}


const result  =  fibonacci(10);

console.log(`Fibonacci(10) = ${result}}`Fibonacci(10) = ${result}`);


class Calculator {

 constructor(initial  =  0) {

 this.value  =  initial;
  }


 add(n) {

 this.value  +=  n;

 return this;
  }


 getValue() {

 return this.value;
  }
}


const calc  =  new Calculator(5);

calc.add(10).add(20);

console.log(calc.getValue());
 // 35

All processing runs entirely in your browser. Your code is never sent to any server, cached, or stored.

JavaScript is the engine of the modern web, but production scripts packed with comments, verbose variable names, and deep indentation can significantly inflate file sizes. Our free online JavaScript Minifier and Beautifier handles both sides of the optimization workflow: compress scripts by stripping comments, whitespace, and unnecessary characters for production deployment, or beautify minified or obfuscated JS into clean, properly indented, syntax-highlighted code for debugging and maintenance. Every keystroke is instantly tokenized — keywords, identifiers, strings (single, double, and template literals), numbers, regex literals, comments, operators, and punctuation each receive distinct coloring for rapid visual comprehension. All processing happens locally in your browser with zero server interaction.

How to Use the JavaScript Formatter

Paste or type your JavaScript — Enter any JavaScript code into the input panel. Functions, classes, arrow functions, template literals, async/await, and ES modules are all supported.
Choose Beautify or Minify — Click Beautify for clean, indented code with full syntax highlighting, or Minify to compress JS into the smallest possible form for production.
Read the color-coded output — Keywords render in purple, strings (single, double, template literal) in green, comments in gray, numbers in orange, regex in red, operators in cyan, and identifiers in white — making code structure immediately parsable.
Copy or download — Use Copy to grab the output to your clipboard, or Download to save as a .js file.

Key Features

Full Syntax Highlighting
Keywords, strings, numbers, regex, template literals, comments, operators, and punctuation each get distinct colors.
Template Literal Support
Correctly handles backtick template strings with embedded expressions while preserving proper indentation and coloring.
Regex Literal Detection
Context-aware regex identification — the tokenizer distinguishes between division operators and regex literals for accurate coloring.
Beautify & Minify
One-click toggle between readable, indented code for development and fully compressed output for production.
Real-Time Processing
Every keystroke re-tokenizes and reformats the output instantly — no submit buttons, no delays.
100% Client-Side
All formatting runs in your browser. No uploads, no server processing — your JavaScript stays private.

When to Use a JavaScript Minifier & Beautifier

Production Optimization: Minify your JavaScript before deployment to reduce file size by 30–60%. This directly improves page load times, Time to Interactive (TTI), and Core Web Vitals.
Reverse-Engineering Bundles: Beautify webpack, Vite, or esbuild output bundles to understand what third-party libraries are shipping and identify unused code.
Debugging Minified Code: When a production error stack trace points to minified code, beautify the relevant script to understand the logic surrounding the error.
Code Review: Standardize formatting before submitting PRs. Consistent indentation and spacing reduces diff noise and makes changes easier to review.
Learning and Analysis: Beautify code snippets from tutorials, Stack Overflow, or documentation to study their structure with color-coded syntax highlighting.

Frequently Asked Questions

How much file size reduction can minification achieve?

JavaScript minification typically reduces file size by 30–60%. Heavily commented, widely spaced code with long variable names sees the largest reduction. Combined with gzip or Brotli compression at the HTTP level, total transfer size reductions often exceed 80%. For maximum optimization, combine minification with tree shaking and code splitting in your build pipeline.

Does minification change how my code executes?

No. This tool performs safe minification that only removes non-functional characters — comments, unnecessary whitespace, and optional semicolons. It never changes variable names, function signatures, or logic. The beautify step reconstructs readable formatting from any minified input without altering semantics.

Can I beautify code minified by terser, UglifyJS, or esbuild?

Yes. The beautifier works with code compressed by any tool — terser, UglifyJS, esbuild, SWC, Google Closure Compiler, or browser-specific minifiers. The tokenizer operates at the character level and reconstructs proper indentation regardless of which tool produced the minified output.

Does this tool support TypeScript or JSX?

This tool is designed for plain JavaScript (ES5 through ES2024+). While TypeScript and JSX code will be formatted, type annotations and JSX elements may not receive optimal indentation or syntax coloring. For TypeScript-specific formatting, consider using Prettier or the TypeScript compiler's formatter.

Is my code safe when using this tool?

Absolutely. All tokenization, formatting, and highlighting happens entirely in your browser. Your JavaScript never leaves your device — no uploads, no server processing, no logging. Disconnect from the internet and the tool keeps working.

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