cssmin.js

/**
 * cssmin.js
 * Author: Stoyan Stefanov - http://phpied.com/
 * This is a JavaScript port of the CSS minification tool
 * distributed with YUICompressor, itself a port
 * of the cssmin utility by Isaac Schlueter - http://foohack.com/
 * Permission is hereby granted to use the JavaScript version under the same
 * conditions as the YUICompressor (original YUICompressor note below).
 */

/*
 * YUI Compressor
 * Author: Julien Lecomte - http://www.julienlecomte.net/
 * Copyright (c) 2009 Yahoo! Inc. All rights reserved.
 * The copyrights embodied in the content of this file are licensed
 * by Yahoo! Inc. under the BSD (revised) open source license.
 */

define(function (require, exports, module) {

    "use strict";

    var CSSMin = {

        go: function (css, linebreakpos) {

            var startIndex = 0,
                endIndex = 0,
                iemac = false,
                preserve = false,
                i = 0,
                max = 0,
                preservedTokens = [],
                token = '';

            // preserve strings so their content doesnt get accidentally minified
            css = css.replace(/("([^\\"]|\\.|\\)*")|('([^\\']|\\.|\\)*')/g, function (match) {
                var quote = match[0];
                preservedTokens.push(match.slice(1, -1));
                return quote + "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___" + quote;
            });

            // Remove all comment blocks...
            while ((startIndex = css.indexOf("/*", startIndex)) >= 0) {
                preserve = css.length > startIndex + 2 && css[startIndex + 2] === '!';
                endIndex = css.indexOf("*/", startIndex + 2);
                if (endIndex < 0) {
                    if (!preserve) {
                        css = css.slice(0, startIndex);
                    }
                } else if (endIndex >= startIndex + 2) {
                    if (css[endIndex - 1] === '\\') {
                        // Looks like a comment to hide rules from IE Mac.
                        // Leave this comment, and the following one, but shorten them
                        css = css.slice(0, startIndex) + "/*\\*/" + css.slice(endIndex + 2);
                        startIndex += 5;
                        iemac = true;
                    } else if (iemac && !preserve) {
                        css = css.slice(0, startIndex) + "/**/" + css.slice(endIndex + 2);
                        startIndex += 4;
                        iemac = false;
                    } else if (!preserve) {
                        css = css.slice(0, startIndex) + css.slice(endIndex + 2);
                    } else {
                        // preserve
                        token = css.slice(startIndex + 3, endIndex); // 3 is "/*!".length
                        preservedTokens.push(token);
                        css = css.slice(0, startIndex + 2) + "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___" + css.slice(endIndex);
                        if (iemac) iemac = false;
                        startIndex += 2;
                    }
                }
            }

            // Normalize all whitespace strings to single spaces. Easier to work with that way.
            css = css.replace(/\s+/g, " ");

            // Remove the spaces before the things that should not have spaces before them.
            // But, be careful not to turn "p :link {...}" into "p:link{...}"
            // Swap out any pseudo-class colons with the token, and then swap back.
            css = css.replace(/(^|\})(([^\{:])+:)+([^\{]*\{)/g, function (m) {
                return m.replace(":", "___YUICSSMIN_PSEUDOCLASSCOLON___");
            });
            css = css.replace(/\s+([!{};:>+\(\)\],])/g, '$1');
            css = css.replace(/___YUICSSMIN_PSEUDOCLASSCOLON___/g, ":");

            // retain space for special IE6 cases
            css = css.replace(/:first-(line|letter)({|,)/g, ":first-$1 $2");

            // no space after the end of a preserved comment
            css = css.replace(/\*\/ /g, '*/');


            // If there is a @charset, then only allow one, and push to the top of the file.
            css = css.replace(/^(.*)(@charset "[^"]*";)/gi, '$2$1');
            css = css.replace(/^(\s*@charset [^;]+;\s*)+/gi, '$1');

            // Put the space back in some cases, to support stuff like
            // @media screen and (-webkit-min-device-pixel-ratio:0){
            css = css.replace(/\band\(/gi, "and (");


            // Remove the spaces after the things that should not have spaces after them.
            css = css.replace(/([!{}:;>+\(\[,])\s+/g, '$1');

            // remove unnecessary semicolons
            css = css.replace(/;+}/g, "}");

            // Replace 0(px,em,%) with 0.
            css = css.replace(/([\s:])(0)(px|em|%|in|cm|mm|pc|pt|ex)/gi, "$1$2");

            // Replace 0 0 0 0; with 0.
            css = css.replace(/:0 0 0 0;/g, ":0;");
            css = css.replace(/:0 0 0;/g, ":0;");
            css = css.replace(/:0 0;/g, ":0;");
            // Replace background-position:0; with background-position:0 0;
            css = css.replace(/background-position:0;/gi, "background-position:0 0;");

            // Replace 0.6 to .6, but only when preceded by : or a white-space
            css = css.replace(/(:|\s)0+\.(\d+)/g, "$1.$2");

            // Shorten colors from rgb(51,102,153) to #336699
            // This makes it more likely that itll get further compressed in the next step.
            css = css.replace(/rgb\s*\(\s*([0-9,\s]+)\s*\)/gi, function () {
                var rgbcolors = arguments[1].split(',');
                for (var i = 0; i < rgbcolors.length; i++) {
                    rgbcolors[i] = parseInt(rgbcolors[i], 10).toString(16);
                    if (rgbcolors[i].length === 1) {
                        rgbcolors[i] = '0' + rgbcolors[i];
                    }
                }
                return '#' + rgbcolors.join('');
            });


            // Shorten colors from #AABBCC to #ABC. Note that we want to make sure
            // the color is not preceded by either ", " or =. Indeed, the property
            //     filter: chroma(color="#FFFFFF");
            // would become
            //     filter: chroma(color="#FFF");
            // which makes the filter break in IE.
            css = css.replace(/([^"'=\s])(\s*)#([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])([0-9a-f])/gi, function () {
                var group = arguments;
                if (
                    group[3].toLowerCase() === group[4].toLowerCase() &&
                    group[5].toLowerCase() === group[6].toLowerCase() &&
                    group[7].toLowerCase() === group[8].toLowerCase()
                ) {
                    return (group[1] + group[2] + '#' + group[3] + group[5] + group[7]).toLowerCase();
                } else {
                    return group[0].toLowerCase();
                }
            });


            // Remove empty rules.
            css = css.replace(/[^\};\{\/]+\{\}/g, "");

            if (linebreakpos >= 0) {
                // Some source control tools dont like it when files containing lines longer
                // than, say 8000 characters, are checked in. The linebreak option is used in
                // that case to split long lines after a specific column.
                startIndex = 0;
                i = 0;
                while (i < css.length) {
                    if (css[i++] === '}' && i - startIndex > linebreakpos) {
                        css = css.slice(0, i) + '\n' + css.slice(i);
                        startIndex = i;
                    }
                }
            }

            // Replace multiple semi-colons in a row by a single one
            // See SF bug #1980989
            css = css.replace(/;;+/g, ";");

            // restore preserved comments and strings
            for (i = 0, max = preservedTokens.length; i < max; i++) {
                css = css.replace("___YUICSSMIN_PRESERVED_TOKEN_" + i + "___", preservedTokens[i]);
            }

            // Trim the final string (for any leading or trailing white spaces)
            css = css.replace(/^\s+|\s+$/g, "");

            // Fix calc minification
            css = css.replace(/calc((.?)+(.?))/g, "calc($1 + $2)");

            // Fix calc minification when using -webkit- (produces double "((")

            css = css.replace(/calc\(\(/g, "calc(");

            console.log("css compressed");

            return css;

        }

    }

    exports.CSSMin = CSSMin;

});