Node进程为什么不会自动退出呢?

Question

const https = require("https");
const http = require("http");
const fs = require("fs");

const browser = {
  "User-Agent":
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36",
};

const httpP = (...props) =>
  new Promise((resolve, reject) => {
    const req = http.request(...props, function (req) {
      const { statusCode } = req;
      // console.log("httpP", statusCode);
      if (statusCode >= 200 && statusCode < 300) {
        resolve(req);
      } else {
        reject(req);
      }
    });
    req.end();
  });

const httpsP = (...props) =>
  new Promise((resolve, reject) => {
    const req = https.request(...props, function (req) {
      const { statusCode } = req;
      // console.log("httpsP", statusCode);
      if (statusCode >= 200 && statusCode < 300) {
        resolve(req);
      } else {
        reject(req);
      }
    });
    req.on("error", function (err) {
      console.log("请求报错", err);
      reject(req);
    });
    req.end();
  });

const getData = (req) =>
  new Promise((resolve, reject) => {
    if (req.on) {
      let data = "";
      req.on("data", function (chunk) {
        data += chunk;
      });
      req.on("end", function () {
        resolve(data);
      });
    } else {
      reject(req);
    }
  });

function getImgUrlFormDocument(document, imgProps = "src") {
  const img = document.match(/(<img(.|\n)*?)>/g);
  if (imgProps === "img") {
    return img;
  }

  const imgUrlProps = new RegExp(`(${imgProps}=['"].*?)['"]`, "g");
  const imgUrl = img
    .map((item) => item.match(imgUrlProps) && item.match(imgUrlProps)[0])
    .filter((item) => item);
  if (!imgUrl.length) {
    throw new Error(`未匹配img属性${imgProps}`);
  }
  return imgUrl;
}

const saveImg = (imgData, saveLoaclPath, fileName) =>
  new Promise((resolve, reject) => {
    fs.mkdir(saveLoaclPath, { recursive: true }, function () {
      fs.writeFile(saveLoaclPath + "/" + fileName, imgData, "binary", function (
        err
      ) {
        if (err) {
          reject(err);
          return console.log("图片保存失败", err);
        }
        resolve(`${saveLoaclPath.slice(2)}/${fileName} save success !!!`);
        // console.log(`${saveLoaclPath.slice(2)}/${fileName} save success !!!`);
      });
    });
  });

const query = (page) =>
  httpsP(`https://www.doutula.com/photo/list/?page=${page}`, browser)
    // 获取html
    .then((req) => getData(req))
    // 获取页面图片的路径
    .then((data) =>
      getImgUrlFormDocument(data, "data-original").map((item) =>
        item.slice(15, -1)
      )
    )
    // 请求图片
    .then((img) => Promise.all(img.map((item) => httpP(item, browser))))
    // 保存图片数据
    .then((dataAll) =>
      dataAll.map((item) => {
        item.setEncoding("binary");
        const path = item.connection._httpMessage.path;
        return { data: getData(item), name: path.split("/").pop() };
      })
    )
    .then(
      (imgData) =>
        Promise.all(
          imgData.map((item) =>
            item.data.then((imgData) =>
              saveImg(imgData, `./Biaoqing/第${page}页`, item.name)
            )
          )
        )
      // imgData.forEach((item, index) => {
      //   item.data.then((imgData) => {
      //     saveImg(imgData, `./Biaoqing/第${page}页`, item.name);
      //   });
      // })
    )
    .then((result) => console.log(`./Biaoqing/第${page}页`, result))
    .catch((err) => console.error("ERROR: ", err));

Promise.all(
  Array.from({ length: 5 }).map((item, index) => query(index + 1))
).then(() => console.log("全部请求完成!!!"));

运行程序的时候没有报错,图片也保存了,但是程序运行完不会退出,到底是什么原因?

Answer 1

我试了一下5页表情都保存成功了

Answer 2

程序不会退出是指开发的时候关闭不了node？
是的话可以试试这个nodemon
https://www.jianshu.com/p/3b3...