the problem with the old code is res.on ("end",.) Is asynchronous, and maybe titleHref is still empty. Now I have updated the code to solve this problem, but how to print the resulting ans array, print is Synchronize, always print out empty data.

New Code:

const cheerio = require("cheerio");
const http = require("http");
const iconv = require("iconv-lite");

let baseUrl = "http://www.ygdy8.net/html/gndy/dyzz/list_23_";
let Host = "http://www.ygdy8.net/";

const totalPage = 2; //
let ans = [];
//
function getTitleHref(url,page) {
  let startUrl = url+page+".html";
  http.get(startUrl,function(res) {
    const { statusCode } = res;
    let chunks = [];
    res.on("data",function(chunk){
      chunks.push(chunk);
    });
    res.on("end",function(){
      let title = [];
      
      let html = iconv.decode(Buffer.concat(chunks),"gb2312");
      let $ = cheerio.load(html, {decodeEntities: false});
      // console.log($);
      $(".co_content8 .ulink").each(function(i,d) {
        let $d = $(d);
        let titleHref = [];
        titleHref.push({
          href: $d.attr("href")
        });
        getLink(titleHref)
      });
      // console.log(ans);
    });  
  });
}


// /*
//
function getLink(titleHref) {
  console.log("getLink");
  console.log(titleHref);
  if(titleHref) {
    titleHref.forEach(function(v,k) {
      console.log("~~~~~~~~~~~~~~~~~~~~");
      let infoUrl = Host + v.href;
      // console.log(infoUrl);
    
        http.get(infoUrl,function(res) {
          const { statusCode } = res;
          const contentType = res.headers["content-type"];
        
          let error;
          if (statusCode !== 200) {
            error = new Error("\n" +
                             `: ${statusCode}`);
          } 
          if (error) {
            console.error(error.message);
            // 
            res.resume();
            return;
          }
          console.log("getlink http");
          let chunks = [];
          res.on("data",function(chunk) {  
            chunks.push(chunk);
          });
          res.on("end", function(){
            try {
              let html = iconv.decode(Buffer.concat(chunks),"gb2312");
              let $ = cheerio.load(html, {decodeEntities: false});
              let bt = "";
              bt = $("-sharpZoom td").children("a").attr("href");
              // console.log(bt);
              // console.log(typeof bt)
              ans.push(bt);
            }catch (e) {
              console.error("bt",e.message);
            }
          })
        }).on("error", (e) => {
          console.error(`: ${e.message}`);
        });
    });
  }
};
// */
for(let i = 1; i <= totalPage; iPP) {
  getTitleHref(baseUrl,i);
};

-- split line-

const cheerio = require("cheerio");
const http = require("http");
const iconv = require("iconv-lite");

let baseUrl = "http://www.ygdy8.net/html/gndy/dyzz/list_23_";
let Host = "http://www.ygdy8.net/";
let titleHref = [];
const totalPage = 1; //
let res = [];
//
function getTitleHref(url,page) {
  let startUrl = url+page+".html";
  http.get(startUrl,function(res) {
    let chunks = [];

    res.on("data",function(chunk){
      chunks.push(chunk);
    });
    res.on("end",function(){
      let title = [];
      let html = iconv.decode(Buffer.concat(chunks),"gb2312");
      let $ = cheerio.load(html, {decodeEntities: false});
      // console.log($);
      $(".co_content8 .ulink").each(function(i,d) {
        let $d = $(d);
        titleHref.push({
          href: $d.attr("href")
        });
      });
      console.log(titleHref);
    });
    if(page <= totalPage) {
      getTitleHref(url,PPpage);
    }else {
      console.log(page);
      getLink(titleHref);
    }
   
  });
}

//
function getLink(titleHref) {
  console.log("getLink");

  titleHref.forEach(function(v,k) {
    console.log("~~~~~~~~~~~~~~~~~~~~");
    let infoUrl = Host + v.href;
    console.log(infoUrl);
    // try {
      http.get(infoUrl,function(res) {
        console.log("getlink http");
        
        let chunks = [];
        res.on("data",function(chunk) {
          chunks.push(chunk);
        });
        res.on("end", function(){
          let html = iconv.decode(Buffer.concat(chunks),"gb2312");
          let $ = cheerio.load(html, {decodeEntities: false});
          
          
          let reg = /.*/;
          let info = "";
          let bt = "";
          let textInfo = $(".co_content8 -sharpZoom p").eq(0).text();
          info = textInfo.match(reg)[0];
          bt = $("-sharpZoom td").children("a").attr("href");
          res.push({
            Info:info,
            Bt:bt
          });
          console.log(res);
        })
        //
        //res.on("error",function(){
        //  console.log("error");
        //})
      })
  // }catch(e) {
  //   console.log(e);
  // }
  });
};

getTitleHref(baseUrl,1)

if there is too much asynchronism in the above code, I don"t know what the problem is. Ask node to instruct the titleHref.forEach in the, getLink () function, and the node thread will collapse. Console.log ("enter getlink http") is also not printed