问下比较基础的问题

var eventproxy = require('eventproxy'); var superagent = require('superagent'); var cheerio = require('cheerio'); var url = require('url');

var cnodeUrl = 'https://cnodejs.org/';

superagent.get(cnodeUrl) .end(function (err, res) { if (err) { return console.error(err); } var topicUrls = []; var $ = cheerio.load(res.text); $('#topic_list .topic_title').each(function (idx, element) { var $element = $(element); var href = url.resolve(cnodeUrl, $element.attr('href')); topicUrls.push(href); });

var ep = new eventproxy();

ep.after('topic_html', topicUrls.length, function (topics) {
  topics = topics.map(function (topicPair) {
    var topicUrl = topicPair[0];
    var topicHtml = topicPair[1];
    var $ = cheerio.load(topicHtml);
    return ({
      title: $('.topic_full_title').text().trim(),
      href: topicUrl,
      comment1: $('.reply_content').eq(0).text().trim(),
    });
  });

  console.log('final:');
  console.log(topics);
});

topicUrls.forEach(function (topicUrl) {
  superagent.get(topicUrl)
    .end(function (err, res) {
      console.log('fetch ' + topicUrl + ' successful');
     ** ep.emit('topic_html', [topicUrl, res.text]);**
    });
});

});

中的 [topicUrl, res.text] 是什么意思？？？