notes/node_modules/postcss-value-parser/lib/walk.js

module.exports = function walk(nodes, cb, bubble) {
    var i, max, node, result;

    for (i = 0, max = nodes.length; i < max; i += 1) {
        node = nodes[i];
        if (!bubble) {
            result = cb(node, i, nodes);
        }

        if (result !== false && node.type === 'function' && Array.isArray(node.nodes)) {
            walk(node.nodes, cb, bubble);
        }

        if (bubble) {
            cb(node, i, nodes);
        }
    }
};