php class Minify

Minify.php

namespace YourNamespace;

class Minify {

	/*
		Use:

		Minify::html( string )
		Minify::css( string )
		Minify::js( string )

	 */

	/**
	 * Constructor.
	 *
	 */
	public function __construct() {}


	public static function html( $html ) {

		if ( trim( $html ) === '' )
			return $html;

		// Remove extra white-space(s) between HTML attribute(s)
		$html = preg_replace_callback('#<([^\/\s<>!]+)(?:\s+([^<>]*?)\s*|\s*)(\/?)>#s', function( $matches ) {

			return '<' . $matches[1] . preg_replace('#([^\s=]+)(\=([\'"]?)(.*?)\3)?(\s+|$)#s', ' $1$2', $matches[2]) . $matches[3] . '>';
		}, str_replace( "\r", "", $html ) );

		// Minify inline CSS declaration(s)
		if ( strpos( $html, ' style=' ) !== false ) {

			$html = preg_replace_callback('#<([^<]+?)\s+style=([\'"])(.*?)\2(?=[\/\s>])#s', function( $matches ) {

				return '<' . $matches[1] . ' style=' . $matches[2] . Minify::css($matches[3]) . $matches[2];
			}, $html);
		}

		// Handle style tags
		if ( strpos( $html, '</style>' ) !== false ) {

			$html = preg_replace_callback('#<style(.*?)>(.*?)</style>#is', function( $matches ) {

				return '<style' . $matches[1] .'>'. Minify::css($matches[2]) . '</style>';
			}, $html);
		}

		// Handle script tags
		if ( strpos( $html, '</script>' ) !== false ) {

			$html = preg_replace_callback('#<script(.*?)>(.*?)</script>#is', function( $matches ) {

				return '<script' . $matches[1] .'>'. Minify::js($matches[2]) . '</script>';
			}, $html);
		}

		$html = preg_replace(
			[
				// t = text
				// o = tag open
				// c = tag close

				//  1 - Keep important white-space(s) after self-closing HTML tag(s)
				'#<(img|input)(>| .*?>)#s',

				//  2 - Remove a line break and two or more white-space(s) between tag(s)
				'#(<!--.*?-->)|(>)(?:\n*|\s{2,})(<)|^\s*|\s*$#s',

				//  3 - t+c || o+t
				'#(<!--.*?-->)|(?<!\>)\s+(<\/.*?>)|(<[^\/]*?>)\s+(?!\<)#s',

				//  4 - o+o || c+c
				'#(<!--.*?-->)|(<[^\/]*?>)\s+(<[^\/]*?>)|(<\/.*?>)\s+(<\/.*?>)#s',

				//  5 - c+t || t+o || o+t -- separated by long white-space(s)
				'#(<!--.*?-->)|(<\/.*?>)\s+(\s)(?!\<)|(?<!\>)\s+(\s)(<[^\/]*?\/?>)|(<[^\/]*?\/?>)\s+(\s)(?!\<)#s',

				//  6 - empty tag
				'#(<!--.*?-->)|(<[^\/]*?>)\s+(<\/.*?>)#s',

				//  7 - reset previous fix
				'#<(img|input)(>| .*?>)<\/\1>#s',

				//  8 - clean up ...
				'#(&nbsp;)&nbsp;(?![<\s])#',

				//  9 - --ibid
				'#(?<=\>)(&nbsp;)(?=\<)#',

				// 10 - Remove HTML comment(s) except IE comment(s)
				'#\s*<!--(?!\[if\s).*?-->\s*|(?<!\>)\n+(?=\<[^!])#s'
			],
			[
				'<$1$2</$1>',     //  1
				'$1$2$3',         //  2
				'$1$2$3',         //  3
				'$1$2$3$4$5',     //  4
				'$1$2$3$4$5$6$7', //  5
				'$1$2$3',         //  6
				'<$1$2',          //  7
				'$1 ',            //  8
				'$1',             //  9
				"",               // 10
			],
			$html
		);

		return $html;
	}

	public static function css( $css ) {

		if ( trim( $css ) === '' )
			return $css;

		$css = preg_replace(
			[
				//  1 - Remove comment(s)
				'#("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\')|\/\*(?!\!)(?>.*?\*\/)|^\s*|\s*$#s',

				//  2 - Remove unused white-space(s)
				'#("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\'|\/\*(?>.*?\*\/))|\s*+;\s*+(})\s*+|\s*+([*$~^|]?+=|[{};,>~]|\s(?![0-9\.])|!important\b)\s*+|([[(:])\s++|\s++([])])|\s++(:)\s*+(?!(?>[^{}"\']++|"(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\')*+{)|^\s++|\s++\z|(\s)\s+#si',

				//  3 - Replace `0(cm|rem|em|ex|in|mm|pc|pt|px|vh|vw|%)` with `0`
				'#(?<=[\s:])(0)(cm|rem|em|ex|in|mm|pc|pt|px|vh|vw|%)#si',

				//  4 - Replace `:0 0 0 0` with `:0`
				'#:(0\s+0|0\s+0\s+0\s+0)(?=[;\}]|\!important)#i',

				//  5 - Replace `background-position:0` with `background-position:0 0`
				'#(background-position):0(?=[;\}])#si',

				//  6 - Replace `0.6` with `.6`, but only when preceded by `:`, `,`, `-` or a white-space
				'#(?<=[\s:,\-])0+\.(\d+)#s',

				//  7/8 - Minify string value
				'#(\/\*(?>.*?\*\/))|(?<!content\:)([\'"])([a-z_][a-z0-9\-_]*?)\2(?=[\s\{\}\];,])#si',
				'#(\/\*(?>.*?\*\/))|(\burl\()([\'"])([^\s]+?)\3(\))#si',

				//  9 - Minify HEX color code
				'#(?<=[\s:,\-]\#)([a-f0-6]+)\1([a-f0-6]+)\2([a-f0-6]+)\3#i',

				// 10 - Replace `(border|outline):none` with `(border|outline):0`
				'#(?<=[\{;])(border|outline):none(?=[;\}\!])#',

				// 11 - Remove empty selector(s)
				'#(\/\*(?>.*?\*\/))|(^|[\{\}])(?:[^\s\{\}]+)\{\}#s',
			],
			[
				'$1',             //  1
				'$1$2$3$4$5$6$7', //  2
				'$1',             //  3
				':0',             //  4
				'$1:0 0',         //  5
				'.$1',            //  6
				'$1$3',           //  7
				'$1$2$4$5',       //  8
				'$1$2$3',         //  9
				'$1:0',           // 10
				'$1$2',           // 11
			],
			$css
		);

		return trim( $css );
	}

	public static function js( $js ) {

		if ( trim( $js ) === '' )
			return $js;

	    $js = preg_replace(
			[
				// 1 - Remove comment(s)
				'#\s*("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\')\s*|\s*\/\*(?!\!|@cc_on)(?>[\s\S]*?\*\/)\s*|\s*(?<![\:\=])\/\/.*(?=[\n\r]|$)|^\s*|\s*$#',

				// 2 - Remove white-space(s) outside the string and regex
				'#("(?:[^"\\\]++|\\\.)*+"|\'(?:[^\'\\\\]++|\\\.)*+\'|\/\*(?>.*?\*\/)|\/(?!\/)[^\n\r]*?\/(?=[\s.,;]|[gimuy]|$))|\s*([!%&*\(\)\-=+\[\]\{\}|;:,.<>?\/])\s*#s',

				// 3 - Remove the last semicolon
				'#;+\}#',

				// 4 - Minify object attribute(s) except JSON attribute(s). From `{'foo':'bar'}` to `{foo:'bar'}`
				'#([\{,])([\'])(\d+|[a-z_][a-z0-9_]*)\2(?=\:)#i',

				// 5 - --ibid. From `foo['bar']` to `foo.bar`
				'#([a-z0-9_\)\]])\[([\'"])([a-z_][a-z0-9_]*)\2\]#i',
			],
			[
				'$1',    // 1
				'$1$2',  // 2
				'}',     // 3
				'$1$3',  // 4
				'$1.$3', // 5
			],
			$js
		);

		return $js;
	}

}