Function compress

lib/compress.js:123–196

(ast, options)

}

export default function compress(ast, options) {
    ast = ast || { type: 'StyleSheet', loc: null, children: new List() };
    options = options || {};

    const compressOptions = {
        logger: typeof options.logger === 'function' ? options.logger : function() {},
        restructuring: getRestructureOption(options),
        forceMediaMerge: Boolean(options.forceMediaMerge),
        usage: options.usage ? buildIndex(options.usage) : false
    };
    const output = new List();
    let specialComments = getCommentsOption(options);
    let firstAtrulesAllowed = true;
    let input;
    let chunk;
    let chunkNum = 1;
    let chunkChildren;

    if (options.clone) {
        ast = clone(ast);
    }

    if (ast.type === 'StyleSheet') {
        input = ast.children;
        ast.children = output;
    } else {
        input = wrapBlock(ast);
    }

    do {
        chunk = readChunk(input, Boolean(specialComments));
        compressChunk(chunk.stylesheet, firstAtrulesAllowed, chunkNum++, compressOptions);
        chunkChildren = chunk.stylesheet.children;

        if (chunk.comment) {
            // add \n before comment if there is another content in output
            if (!output.isEmpty) {
                output.insert(List.createItem({
                    type: 'Raw',
                    value: '\n'
                }));
            }

            output.insert(List.createItem(chunk.comment));

            // add \n after comment if chunk is not empty
            if (!chunkChildren.isEmpty) {
                output.insert(List.createItem({
                    type: 'Raw',
                    value: '\n'
                }));
            }
        }

        if (firstAtrulesAllowed && !chunkChildren.isEmpty) {
            const lastRule = chunkChildren.last;

            if (lastRule.type !== 'Atrule' ||