codenothing/CSSCompressor

/**
 * 
 * Font Combinations
 * 
 * @author: Corey Hart <http://www.codenothing.com>
 * @description: Combines font declarations into single property
 * 
 * @before:
 *     .example {
 *         font-weight: bold;
 *         font-size: 12px;
 *         font-family: Helvetica;
 *     }
 * 
 * @after:
 *     .example {
 *         font: bold 12px Helvetica;
 *     }
 * 
 */

var CSSCompressor = global.CSSCompressor;

CSSCompressor.rule({

    name: 'Font Combinations',
    type: CSSCompressor.RULE_TYPE_BLOCK,
    group: 'Font',
    description: "Combines font declarations into single property",

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

        [

            [ 'font-style', 'font-variant', 'font-weight', 'font-size', 'line-height', 'font-family' ],
            [ 'font-style', 'font-variant', 'font-weight', 'font-size', 'font-family' ],
            [ 'font-style', 'font-variant', 'font-size', 'line-height', 'font-family' ],
            [ 'font-style', 'font-variant', 'font-size', 'font-family' ],
            [ 'font-style', 'font-weight', 'font-size', 'line-height', 'font-family' ],
            [ 'font-style', 'font-weight', 'font-size', 'font-family' ],
            [ 'font-variant', 'font-weight', 'font-size', 'line-height', 'font-family' ],
            [ 'font-variant', 'font-weight', 'font-size', 'font-family' ],
            [ 'font-weight', 'font-size', 'line-height', 'font-family' ],
            [ 'font-weight', 'font-size', 'font-family' ],
            [ 'font-variant', 'font-size', 'line-height', 'font-family' ],
            [ 'font-variant', 'font-size', 'font-family' ],
            [ 'font-style', 'font-size', 'line-height', 'font-family' ],
            [ 'font-style', 'font-size', 'font-family' ],
            [ 'font-size', 'line-height', 'font-family' ],
            [ 'font-size', 'font-family' ]

        ].forEach(function( graph ) {
            var used = [],
                hash = {},
                first = null,
                parts = [],
                newparts = [],
                fsi = -1,
                lhi = -1;

            branch.rules.forEach(function( rule ) {
                if ( graph.indexOf( rule.property ) !== -1 ) {
                    used.push( rule );
                    hash[ rule.property ] = rule;
                }
                else if ( rule.property == 'font' ) {
                    hash[ rule.property ] = true;
                }
            });

            if ( ! hash.font && CSSCompressor.keysInHash( graph, hash ) ) {
                parts = new Array( graph.length );
                first = used[ 0 ];

                used.forEach(function( rule ) {
                    parts[ graph.indexOf( rule.property ) ] = rule.parts.length > 1 ? rule.parts : 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 ]
                        );
                    }
                });

                // Handle font-size/line-height combination
                fsi = graph.indexOf( 'font-size' );
                lhi = graph.indexOf( 'line-height' );
                if ( fsi > -1 && lhi == fsi + 1 ) {
                    parts[ fsi ] = [ parts[ fsi ], '/', parts[ lhi ] ];
                    parts.splice( lhi, 1 );
                }

                // Expand out any nested arrays in the parts
                parts.forEach(function( part ) {
                    if ( CSSCompressor.isArray( part ) ) {
                        newparts.push.apply( newparts, part );
                    }
                    else {
                        newparts.push( part );
                    }
                });

                // Override first property
                first.property = 'font';
                first.parts = newparts;
                used.shift();
                CSSCompressor.removeItems( branch.rules, used );
            }
        });
    }

});