Node.js 利用cheerio制作简单的网页爬虫示例

const https = require('https');const fs = require('fs');const cheerio = require('cheerio');const url = 'https://segmentfault.com/';https.get(url, (res) => {  let html = '';  res.on('data', (data) => {    html += data;  });  res.on('end', () => {    getPageTitle(html);  });}).on('error', () => {  console.log('获取网页信息错误');});function getPageTitle(html) {  const $ = cheerio.load(html);  let chapters = $('.news__item-title');  let data = [];  let index = 0;  let fileName = 'pageTitle.txt';  for (let i = 0; i < chapters.length; i++) {    let chapterTitle = $(chapters[i]).find('a').text().trim();    index++;    data.push(`/n${index}, ${chapterTitle}`);  }  fs.writeFile(fileName, data, 'utf8', (err) => {    if (err) {      console.log('fs文件系统创建新文件失败', err);    }    console.log(`已成功将获取到的标题放入新文件${fileName}文件中`)  })}