JavaScript Minifier
Remove comments and whitespace from JavaScript to reduce file size for production deployments.
JavaScript is the largest contributor to page weight in modern web applications. Minifying JavaScript removes comments, whitespace, and newlines to produce compact code that the browser can download faster. Smaller JavaScript bundles mean faster parse times, less memory pressure, and improved Core Web Vitals scores. This basic JS minifier handles single-line and block comments and collapses whitespace — ideal for simple scripts without complex module syntax.
📋 How to Use This Calculator
Paste your JavaScript code into the input area and click "Minify JavaScript." The tool removes // single-line comments, /* block comments */, leading whitespace from each line, spaces around common operators and delimiters, and all newlines. The output shows the minified code with the file size reduction percentage. Copy the result for use in production. For complex ES6+ modules, React/JSX, or TypeScript, use a dedicated tool like Terser or esbuild which understand the syntax deeply and apply advanced optimizations safely.
💡 Key Facts & Information
This basic minifier applies regex-based transformations: strip // comments and /* */ comments, remove leading whitespace per line, remove spaces around operators ({, }, (, ), [, ], =, +, -, *, /, <, >, !, &, |, ,, ;, :, ?), and remove remaining newlines. This is a conservative, safe approach that avoids risky optimizations. Production-grade minifiers like Terser also rename variables to shorter names (a, b, c), inline constants, remove dead code branches, and optimize expressions — achieving 50–70% reduction versus 20–40% for basic whitespace removal only.