JS Minifier
Advanced logic-based compression for JavaScript. Reduces file size by intelligently stripping comments and whitespace while preserving code integrity.
How to Use the JavaScript Minifier
This tool uses a custom-built tokenizer to safely parse and compress your JavaScript code in the browser. Unlike simple "find and replace" tools, this minifier understands JavaScript context. It can distinguish between a division operator / and a Regular Expression literal /abc/, and it knows never to touch the contents of your strings, even if they contain characters that look like code comments.
Step-by-Step Guide
- Input: Paste your raw JavaScript (ES5, ES6+) into the left-hand panel.
- Configuration:
- Remove Comments: Strips single-line
//and multi-line/* */comments. - Collapse Whitespace: Removes newlines and tabs, and reduces spaces to the minimum required for valid syntax.
- Remove Semicolons: (Experimental) Removes semicolons that are safe to remove according to Automatic Semicolon Insertion (ASI) rules.
- Remove Comments: Strips single-line
- Execute: Click the yellow "Minify JS" button at the bottom.
- Deploy: Copy the output from the right-hand panel and save it as a
.min.jsfile.
Why Minify JavaScript?
Minification is crucial for frontend performance optimization. Large JavaScript bundles are one of the primary causes of slow Time to Interactive (TTI) metrics.
1. Faster Parsing & Execution
While GZIP compression helps with network transfer, the browser still has to parse the uncompressed code. Minified code is smaller and often faster for the JavaScript engine to parse, leading to quicker script execution on low-end mobile devices.
2. Reduced Bandwidth
Removing comments (which are for developers, not machines) and long whitespace sequences can reduce file sizes by 30-50% before GZIP is even applied.