js-micron

JS minifying tool drastically reducing the size of scripts. Inspired by JS Crush.

Installation

• Global installation:

$ npm install -g js-micron

• Local installation:

$ npm install js-micron

# Dev-dependency
$ npm install -D js-micron

How does it work?

js-micron passes your code through uglify-js in order to compress & optimize the code. Then repeated chunks of code are found and replaced with shorter tokens.

Example:

const hello = 'Hello world!';
const name = prompt('What\'s your name?');
console.log(hello);
console.log('Your name is', name);
console.log('Goodbye world!');

Result of uglify-js's work will be something like:

var o = prompt('What\'s your name?');
console.log('Hello world!');
console.log('Your name is', o);
console.log('Goodbye world!');

As you can see, const has been replaced with var (because it's shorter), name has been changed to o (shorter variable name) and variable hello is known at compile-time, so it has been removed completely.

Then repeated chunks are being replaced with tokens:

var o = prompt('What\'s your <01>?');
<02>('Hello <03>!');
<02>('Your <01> is', o);
<02>('Goodbye <03>!');

where are non-printable characters (tokens) (XX is the hexadecimal number of the character).

Then code is minified:

var o=prompt('What\'s your <01>?');<02>('Hello <03>!');<02>('Your <01> is',o);<02>('Goodbye <03>!');

And the last step - replaced chunks and decompressing code is added:

_="var o=prompt('What\'s your <01>?');<02>('Hello <03>!');<02>('Your <01> is',o);<02>('Goodbye <03>!')<01>name<02>console.log<03>name";for($ of "<03><02><01>")with(_.split($))_=join(pop());eval(_)

Of course in this case compression is not effective, but in larger projects result can be impressive.

CLI

Usage: [npx] js-micron [OPTIONS] <INPUT FILE> <OUTPUT FILE>

Options:

• -h, --help Displays help
• -V, --version Displays js-micron's version
• -v, --verbose Verbose output

In-code usage

// ES6
import { compress } from 'js-micron';
// CommonJS
const { compress } = require('js-micron');

const input = `console.log('Hello world!');`;
const output = compress(input);