codenothing/CSSCompressor

/**
 * 
 * Sort Properties
 * 
 * @author: Corey Hart <http://www.codenothing.com>
 * @description: Sorts property-values for a better chance at compression during gzip
 * 
 * @before:
 *     .example {
 *         padding: 10px;
 *         background: green;
 *         margin: 10px;
 *         color: red;
 *     }
 * 
 * @after:
 *     .example {
 *         background: green;
 *         color: red;
 *         margin: 10px;
 *         padding: 10px;
 *     }
 * 
 */

var CSSCompressor = global.CSSCompressor;

CSSCompressor.rule({

    name: 'Sort Properties',
    type: CSSCompressor.RULE_TYPE_BLOCK,
    group: 'GZIP',
    description: "Sorts property-values for a better chance at compression during gzip",
    priority: CSSCompressor.PRIORITY_LOW,

    callback: function( branch, compressor ) {
        if ( ! branch.rules || ! branch.rules.length ) {
            return;
        }

        var copy = branch.rules.slice( 0 );
        branch.rules.sort(function( a, b ) {
            if ( a.property && a.property.length && b.property && b.property.length ) {
                if ( a.property == b.property ) {
                    if ( a.parts && a.parts.length && b.parts && b.parts.length ) {
                        return a.parts.join( '' ) > b.parts.join( '' ) ? 1 : -1;
                    }
                    else {
                        return 0;
                    }
                }
                else {
                    return a.property > b.property ? 1 : -1;
                }
            }
            else {
                return a.property && a.property.length ? 1 : -1;
            }
        });

        if ( ! CSSCompressor.objectsMatch( copy, branch.rules ) ) {
            compressor.rerun = true;
            compressor.log( 'Sorted rule block properties', branch.position );
        }
    }

});