codenothing/CSSCompressor

var CSSCompressor = global.CSSCompressor,
    rvalueseparator = /^\/|,$/,
    rselectorbreak = /^[\~\+\*\,>]$/;

// Const
CSSCompressor.FORMAT_NONE = 'none';

// Tree rendering
function render( css, branches ) {
    branches.forEach(function( branch, branchIndex ) {
        var newparts = [], nextBranch = branches[ branchIndex + 1 ], selector = '';

        // Comments
        if ( branch.comment ) {
            css += branch.comment;
        }
        // Ruleset
        else if ( branch.selector ) {
            branch.parts.forEach(function( part, i ) {
                var prev = branch.parts[ i - 1 ];

                if ( selector.length && ! rselectorbreak.exec( part ) && ! rselectorbreak.exec( prev ) ) {
                    selector += ' ';
                }

                selector += CSSCompressor.isArray( part ) ? part.join( '' ) : part;
            });

            // Add selector
            css += selector + "{";

            // Add rules
            branch.rules.forEach(function( rule, i ) {
                var value = '';
                rule.parts.forEach(function( part, ri ) {
                    var prev = rule.parts[ ri - 1 ];
                    if ( value.length && part != '!important' && ! rvalueseparator.exec( part ) && ! rvalueseparator.exec( prev ) ) {
                        value += ' ';
                    }

                    value += part;
                });

                // Prop:val
                css += rule.property + ":" + value;

                // Skip last semi-colon
                if ( i < branch.rules.length - 1 ) {
                    css += ';';
                }
            });

            // Closing brace
            css += "}";
        }
        // At rules
        else if ( branch.atrule ) {
            selector = '';
            branch.parts.forEach(function( part, i ) {
                var prev = branch.parts[ i - 1 ];

                if ( selector.length && part != ',' && prev != ',' ) {
                    selector += ' ';
                }

                selector += part;
            });

            // Nested selectors
            if ( branch.branches || branch.rules ) {
                // TODO: Handle atrule selector parts
                css += selector + "{";

                // Add rules
                ( branch.rules || [] ).forEach(function( rule, i ) {
                    var value = '';
                    rule.parts.forEach(function( part, ri ) {
                        var prev = rule.parts[ ri - 1 ];
                        if ( value.length && ! rvalueseparator.exec( part ) && ! rvalueseparator.exec( prev ) ) {
                            value += ' ';
                        }

                        value += part;
                    });

                    // Prop:val
                    css += rule.property + ":" + value;

                    // Skip last semi-colon
                    if ( i < branch.rules.length - 1 ) {
                        css += ';';
                    }
                });

                // Add nested selectors
                if ( branch.branches ) {
                    css += branch.rules && branch.rules.length ? ';' : '';
                    css = render( css, branch.branches );
                }

                // Closing brace
                css += "}";
            }
            // One-liners, @imports
            else {
                css += selector + ";";
            }
        }
    });

    return css;
}

// Format addition
CSSCompressor.format( CSSCompressor.FORMAT_NONE, function( compressor ) {
    return render( '', compressor.branches );
});