codenothing/CSSCompressor

/**
 * 
 * Border, Outline Style Combinations
 * 
 * @author: Corey Hart <http://www.codenothing.com>
 * @description: Combines border & outline expanded properties into single property
 * 
 * @before:
 *     .example {
 *         border-top-width: 2px;
 *         border-top-style: dashed;
 *         border-top-color: blue;
 *     }
 * 
 * @after:
 *     .example {
 *         border-top: 2px dashed blue;
 *     }
 * 
 */

var CSSCompressor = global.CSSCompressor;

CSSCompressor.rule({

    name: 'Border, Outline Style Combinations',
    type: CSSCompressor.RULE_TYPE_BLOCK,
    group: 'Border',
    description: "Combines border & outline expanded properties into single property",

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

        // Both margin and padding work the same way
        [ 'border', 'border-top', 'border-right', 'border-bottom', 'border-left', 'outline' ].forEach(function( prop ) {
            var hash = {},
                used = [],
                parts = [],
                first = null,
                pwidth = prop + '-width',
                pstyle = prop + '-style',
                pcolor = prop + '-color',
                matchKeys = [
                    pwidth,
                    pstyle,
                    pcolor
                ];

            // Build hash table of directionals
            branch.rules.forEach(function( rule ) {
                if ( rule.property == prop || matchKeys.indexOf( rule.property ) > -1 ) {
                    used.push( rule );
                    hash[ rule.property ] = rule;
                }
            });

            // Either all four directionals have to exist, or the shorthand property has to exist
            if ( ( hash[ prop ] && used.length > 1 ) || CSSCompressor.keysInHash( matchKeys, hash ) ) {
                parts = [ '', '', '' ];
                first = used[ 0 ];

                // Override directionals in order that they are used
                used.forEach(function( rule ) {
                    if ( rule.property == prop ) {
                        parts = rule.parts;
                    }
                    else if ( rule.property == pwidth ) {
                        parts[ 0 ] = rule.parts[ 0 ];
                    }
                    else if ( rule.property == pstyle ) {
                        parts[ 1 ] = rule.parts[ 0 ];
                    }
                    else if ( rule.property == pcolor ) {
                        parts[ 2 ] = rule.parts[ 0 ];
                    }

                    // Log the compression
                    if ( rule !== first && rule.position && first.position ) {
                        compressor.log(
                            "Combining '" + rule.property + "' on line " + rule.position.start.line +
                            " with '" + first.property + "' on line " + first.position.start.line,
                            [ rule.position, first.position ]
                        );
                    }
                });

                // Override the first property
                first.property = prop;
                first.parts = parts;
                used.shift();
                CSSCompressor.removeItems( branch.rules, used );
            }
        });
    }

});