cssmin.js

/**
 * node-cssmin
 * A simple module for Node.js that minify CSS
 * Author : Johan Bleuzen
 */

/**
 * 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
* http://developer.yahoo.com/yui/compressor/
* Author: Julien Lecomte - http://www.julienlecomte.net/
* Copyright (c) 2011 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.
*/

module.exports = cssmin;

function cssmin(css, linebreakpos) {

    var startIndex = 0,
        endIndex = 0,
        i = 0, max = 0,
        preservedTokens = [],
        comments = [],
        token = '',
        totallen = css.length,
        placeholder = '';

    // collect all comment blocks...
    while ((startIndex = css.indexOf("/*", startIndex)) >= 0) {
        endIndex = css.indexOf("*/", startIndex + 2);
        if (endIndex < 0) {
            endIndex = totallen;
        }
        token = css.slice(startIndex + 2, endIndex);
        comments.push(token);
        css = css.slice(0, startIndex + 2) + "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + (comments.length - 1) + "___" + css.slice(endIndex);
        startIndex += 2;
    }

    // preserve strings so their content doesn't get accidentally minified
    css = css.replace(/("([^\\"]|\\.|\\)*")|('([^\\']|\\.|\\)*')/g, function (match) {
        var i, max, quote = match.substring(0, 1);

        match = match.slice(1, -1);

        // maybe the string contains a comment-like substring?
        // one, maybe more? put'em back then
        if (match.indexOf("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_") >= 0) {
            for (i = 0, max = comments.length; i < max; i = i + 1) {
                match = match.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___", comments[i]);
            }
        }

        // minify alpha opacity in filter strings
        match = match.replace(/progid:DXImageTransform\.Microsoft\.Alpha\(Opacity=/gi, "alpha(opacity=");

        preservedTokens.push(match);
        return quote + "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___" + quote;
    });

    // strings are safe, now wrestle the comments
    for (i = 0, max = comments.length; i < max; i = i + 1) {

        token = comments[i];
        placeholder = "___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___";

        // ! in the first position of the comment means preserve
        // so push to the preserved tokens keeping the !
        if (token.charAt(0) === "!") {
            preservedTokens.push(token);
            css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
            continue;
        }

        // \ in the last position looks like hack for Mac/IE5
        // shorten that to /*\*/ and the next one to /**/
        if (token.charAt(token.length - 1) === "\\") {
            preservedTokens.push("\\");
            css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
            i = i + 1; // attn: advancing the loop
            preservedTokens.push("");
            css = css.replace("___YUICSSMIN_PRESERVE_CANDIDATE_COMMENT_" + i + "___",  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
            continue;
        }

        // keep empty comments after child selectors (IE7 hack)
        // e.g. html >/**/ body
        if (token.length === 0) {
            startIndex = css.indexOf(placeholder);
            if (startIndex > 2) {
                if (css.charAt(startIndex - 3) === '>') {
                    preservedTokens.push("");
                    css = css.replace(placeholder,  "___YUICSSMIN_PRESERVED_TOKEN_" + (preservedTokens.length - 1) + "___");
                }
            }
        }

        // in all other cases kill the comment
        css = css.replace("/*" + placeholder + "*/", "");
    }


    // 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(/\:/g, "___YUICSSMIN_PSEUDOCLASSCOLON___");
    });

    // Preserve spaces in calc expressions
    css = css.replace(/calc\s*\(\s*(.*?)\s*\)/g, function (m, c) {
       return m.replace(c, c.replace(/\s+/g, "___YUICSSMIN_SPACE_IN_CALC___"));
    });

    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');

    // Restore preserved spaces in calc expressions
    css = css.replace(/___YUICSSMIN_SPACE_IN_CALC___/g, " ");

    // 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$1");
    css = css.replace(/:0 0 0(;|\})/g, ":0$1");
    css = css.replace(/:0 0(;|\})/g, ":0$1");

    // Replace background-position:0; with background-position:0 0;
    // same for transform-origin
    css = css.replace(/(background-position|transform-origin|webkit-transform-origin|moz-transform-origin|o-transform-origin|ms-transform-origin):0(;|\})/gi, function(all, prop, tail) {
        return prop.toLowerCase() + ":0 0" + tail;
    });

    // 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 it'll get further compressed in the next step.
    css = css.replace(/rgb\s*\(\s*([0-9,\s]+)\s*\)/gi, function () {
        var i, rgbcolors = arguments[1].split(',');
        for (i = 0; i < rgbcolors.length; i = i + 1) {
            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();
        }
    });

    // border: none -> border:0
    css = css.replace(/(border|border-top|border-right|border-bottom|border-right|outline|background):none(;|\})/gi, function(all, prop, tail) {
        return prop.toLowerCase() + ":0" + tail;
    });

    // shorter opacity IE filter
    css = css.replace(/progid:DXImageTransform\.Microsoft\.Alpha\(Opacity=/gi, "alpha(opacity=");

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

    if (linebreakpos >= 0) {
        // Some source control tools don't 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) {
            i = i + 1;
            if (css[i - 1] === '}' && 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 = i + 1) {
        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, "");

    return css;

};