JSqueeze: Efficient JavaScript minification in PHP

JSqueeze shrinks / compresses / minifies / mangles Javascript code.

It's a single PHP class that has been developed, maintained and thoroughly tested since 2003 on major JavaScript frameworks (e.g. jQuery).

JSqueeze operates on any parse error free JavaScript code, even when semi-colons are missing.

In term of compression ratio, it compares to YUI Compressor and UglifyJS.

Installation

Through composer:

{
    "require": {
        "patchwork/jsqueeze": "~2.0"
    }
}

Usage

use Patchwork\JSqueeze;

$jz = new JSqueeze();

$minifiedJs = $jz->squeeze(
    $fatJs,
    true,   // $singleLine
    true,   // $keepImportantComments
    false   // $specialVarRx
);

Features

• Removes comments and white spaces.
• Renames every local vars, typically to a single character.
• Keep Microsoft's conditional comments.
• In order to maximise later HTTP compression (deflate, gzip), new variables names are choosen by considering closures, variables' frequency and characters' frequency.
• Can rename also global vars, methods and properties, but only if they are marked special by some naming convention. Use JSqueeze::SPECIAL_VAR_PACKER to rename vars whose name begins with one or more $ or with a single _.
• Renames also local/global vars found in strings, but only if they are marked special.
• If you use with/eval then be careful.

Bonus

• Replaces false/true by !1/!0
• Replaces new Array/Object by []/{}
• Merges consecutive var declarations with commas
• Merges consecutive concatened strings
• Can replace optional semi-colons by line feeds, thus facilitating output debugging.
• Keep important comments marked with /*!...
• Treats three semi-colons ;;; like single-line comments.
• Fix special catch scope across browsers
• Work around buggy-handling of named function expressions in IE<=8

To do?

• foo['bar'] => foo.bar
• {'foo':'bar'} => {foo:'bar'}
• Dead code removal (never used function)
• Munge primitives: var WINDOW=window, etc.

License

This library is free software; you can redistribute it and/or modify it under the terms of the (at your option): Apache License v2.0 (see provided LICENCE.ASL20 file), or GNU General Public License v2.0 (see provided LICENCE.GPLv2 file).