JavaScript Minifier that Keeps Variable Names

What is a JS minifier?

A JavaScript minifier removes comments, collapses whitespace, and tightens the spacing around operators and punctuation so the script parses to the exact same behavior in far fewer bytes. For a script that runs on every page load, shaving even a few hundred bytes adds up across thousands of visits — and unlike CSS, unminified JS also carries readable variable names and comments that reveal implementation details you may not want shipped verbatim.

This tool does a lightweight, regex-based whitespace-and-comment strip in your browser. It does not rename variables or perform dead-code elimination the way a real compressor like Terser does — it's aimed at quick, dependency-free cleanup of a snippet, not replacing your build pipeline.

When to use it

Use it for inline `<script>` blocks, bookmarklets, small utility scripts served outside a bundler, or userscripts where pulling in a full build toolchain isn't worth it. It's also handy for quickly estimating how much of a file's size is just formatting versus actual logic.

For anything that ships to production as part of an app — a React/Vue/Svelte bundle, a Node package — rely on your bundler's minifier (Terser, esbuild, SWC). Those tools parse the AST and can safely rename local variables and remove unreachable branches; a regex-based pass like this one can't do that safely because it doesn't understand JS syntax, only text patterns.

Example

Input:

function greet(name) { // Say hello console.log("Hello " + name); }

Output: function greet(name){console.log("Hello "+name);} — the comment is removed, newlines are collapsed, and spacing around operators and braces is tightened, without changing what the function does.