JavaScript Minifier - DigiKitApp

Strip unnecessary whitespace from JavaScript code.

When should you use this?

Use this to shrink a JavaScript file's size and cut page load time, as the last step before going live.

When shouldn't you use this?

If you need to debug an error in minified code, you'll have a hard time; always debug against the original, formatted code.

Step-by-step

Copy the final, tested version of the script from your editor.
Paste it into the "JavaScript code" field.
Click "Run". The code with whitespace stripped shows up in the result area.
Save the output as a separate file, such as script.min.js, and point your page's script tag at it.
Load the page and check the browser console for errors.

Example

A small business site has a hand-written script that toggles the mobile menu and validates the contact form. It's full of comments and generous indentation because someone will need to edit it later. Before going live, you make a minified copy: the original script.js stays as your working file, and the page loads script.min.js. When something needs changing, you edit the original and minify again. That setup stops the two files from drifting apart and keeps anyone from patching the minified version by hand.

How does JavaScript minification work?

This tool does a light minification: it removes /* ... */ comments, strips leading and trailing whitespace on each line and deletes blank lines, removes lines that consist only of a // comment, and cleans up a trailing // comment on lines that contain no quote marks. Line breaks are kept, so code written without semicolons is not broken. It does not shorten variable names or drop unused code; the saving is clearest in files heavy on comments and indentation.

When minifying

/* ... */ comments are removed anywhere in the text; if a string or regular expression contains “/*”, the code can break.
A trailing // comment on a line that contains a quote is not removed; the tool leaves such lines alone so it does not cut an address (http://...) by mistake.
Lines inside template strings (backticks) are also stripped of indentation; if you use multi-line template text, check the output.
Test the minified file so the browser console shows no errors before publishing. On bigger projects a minifier in your build process saves more.

Things to keep in mind

This tool keeps line breaks, so code written without semicolons is not broken. If you use another minifier that joins lines, ending statements with semicolons first lowers the risk.
If you need to keep a license or copyright comment at the top, check that it survived and add it back by hand if not.
This tool removes whitespace. Tools that also shorten variable names and drop unused code save more, and on bigger projects it's worth adding one to your build process.
Inside template literals (backtick strings), spaces are part of the content. Make sure those strings come through unchanged.

Frequently asked questions

Is the code/data I enter stored anywhere?

No, nothing is sent to a server or stored; processing happens entirely in your browser.

Does it work with large inputs?

Yes, though performance may degrade with very large inputs (several MB or more).

Is this tool free?

Yes, it's completely free for core use and requires no account.