JS Minifier
The JavaScript Minifier compresses JS code by removing whitespace, comments, and shortening variable names where safe. Minified JavaScript loads faster, reducing page load times and improving Core Web Vitals. This minifier removes comments, trims whitespace, and optionally renames local variables to shorter names. It preserves all functionality while reducing file size by 30-60%.
Formula
Minification removes: - Comments (// and /* */) - Whitespace (spaces, tabs, newlines) - Unnecessary semicolons - Dead code (if detectable) - Shortens variable names (local only) Size reduction: 30-60%
Example
Input (180 chars): // Calculate sum function calculateSum(a, b) { const result = a + b; return result; } Output (52 chars): function calculateSum(a,b){return a+b} Savings: 71% size reduction
How to Use
- Paste your JavaScript code into the input field
- Click minify to compress the code
- The output shows minified JavaScript
- Copy the minified code
- Use it in production for faster page loads
Frequently Asked Questions
Does minification break JavaScript?
No. Minification preserves all functionality. It only removes whitespace, comments, and renames local variables (not global ones). The minified code produces the exact same behavior as the original. Always keep the original for debugging.
What is the difference between minify and uglify?
Minify removes whitespace and comments. Uglify (or terser) also renames variables to shorter names and applies other optimizations. Uglify produces smaller files but is more aggressive. Modern tools like Terser combine both approaches.
Should I minify JavaScript in development?
No. Keep JavaScript readable during development. Only minify for production. Most build tools (Webpack, Vite, Rollup) automatically minify JavaScript during production builds using Terser or esbuild.
Can minification cause bugs?
Rarely. If your code relies on function names (like recursive references via arguments.callee) or has missing semicolons that create ambiguity, minification can change behavior. Always test minified code before deploying to production.
How much can I save with JS minification?
Typically 30-60% size reduction. Code with many comments and descriptive variable names sees the largest reduction. Already-compact code sees less. Combined with gzip compression, total savings can reach 80-90%.