JavaScript Optimiser

Improve load times, save costs and find potential JavaScript problems with this useful and easy to use command line tool!

Reduces File Size

This tool reduces the size of your JavaScript using a variety of methods including:

• Removes Comments

  ✂️ Comments are useful when working on a file but not needed in the published version.

• Removes Console Logging

  ✂️ As above, useful for debugging when making programs but not needed in published applications.

• Removes White Space and Empty Lines

  ✂️ To save even more bytes!

• Combines Let / Const Statements

  💥 Multi-line declarations, where possible, are converted to a single line to save more bytes.

• Colour Name Shortening

  🎨 Changing a colours name from a 6 characters to 3 characters (e.g. #00ff00 to #0f0) saves a few more bytes!

Health Check

As well as making the file smaller, the tool also checks for possible problems and suggests improvements:

• Finds Duplicate Functions

  ✔️ Not a common problem, but it checks for multiple functions with the same name.

• Suggests Best Practices

  ✔️ Maybe subjective but tells you if you are not using 'strict mode' or if you are still using 'var' when it should be 'let / const'. Useful when updating old files.

Usage

As it was made more for my use than the public it is very simple to use, all you need to do is give it a file and it will produce a compressed version called 'compiled.js', e.g.:

>jsopt trak.js
JavaScript Optimiser v0.# Go (##/##/2026) by ssjx (https://ssjx.co.uk)
======================================================================
Input:   trak.js
Output:  compiled.js

JavaScript Health Check
-----------------------
* Missing 'use strict' at the top of file.
* 'var' found, consider using 'let' or 'const' instead.
* Duplicate function(s):
        loadImages

The errors above were created to make sure the tool worked! The test file (trak.js) size went from 59KB to 38KB which is nearly a third off the size!

To create a differently named output file, just add that onto the end of the command e.g.:

>jsopt trak.js newfile.js
JavaScript Optimiser v0.# Go (##/##/2026) by ssjx (https://ssjx.co.uk)
======================================================================
Input:   trak.js
Output:  newfile.js

JavaScript Health Check
-----------------------
No problems found!

⚠️ Please note that this tool is not perfect, and it will likely fail on complex or convoluted JavaScript files. As I use it more and more on my own work, it may get better over time so check back for updates!

Download

585KB 7Zip
Version 0.6 (15/04/2026)