stringify.js

function attrString(attrs) {
    var buff = [];
    for (var key in attrs) {
        buff.push(key + '=' + attrs[key]);
    }
    if (!buff.length) {
        return '';
    }
    return ' ' + buff.join(' ');
}

function stringify(buff, doc) {
    switch (doc.type) {
    case 'text':
        return buff + doc.content;
    case 'tag':
        buff += '<' + doc.name + (doc.attrs ? attrString(doc.attrs) : '') + (doc.voidElement ? '/>' : '>');
        if (doc.voidElement) {
            return buff;
        }
        return buff + doc.children.reduce(stringify, '') + '</' + doc.name + '>';
    }
}

module.exports = function (doc) {
    return doc.reduce(function (token, rootEl) {
        return token + stringify('', rootEl);
    }, '');
};