JavaScript Minifier

JavaScript Minifier removes comments and unnecessary whitespace, which is the part of minification that is always safe. Strings, template literals and regular expressions are detected and passed through untouched, because a brace or a slash inside one looks exactly like code and a minifier that cannot tell the difference corrupts the file.

What this tool deliberately does not do is rename variables. Serious minifiers shrink files much further by turning descriptive names into single letters, and doing that correctly requires parsing the whole program and understanding every scope. Doing it almost correctly breaks code in ways that only show up in production, which is the worst possible place to find out.

So the expected saving here is modest: usually twenty to forty percent on commented source, and considerably less once gzip is applied. For a production build, use a proper minifier in your pipeline. For shrinking a snippet you are about to inline in a page, this does the job without risk.

• Removes line and block comments
• Collapses whitespace and indentation
• Strings, template literals and regex preserved exactly
• Keeps semicolons, so automatic insertion is never relied on
• Option to keep licence comments
• Never renames variables, so nothing can break
• Shows original size, minified size and percentage saved

The javascript minifier is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

• Shrinking a small script before inlining it
• Removing comments from a snippet you are sharing
• Reducing the size of an inline analytics or widget script
• Measuring how much of a file is comments
• Compressing a script for an environment with no build step