我有一個Nodejs腳本，其詳細信息如下所示：1）它向API請求以獲取城市列表，它將獲取JSON數(shù)組。使用此數(shù)組，我使用進行循環(huán)forEach。2）在每次迭代（第二循環(huán)）時，我確實再次向API請求以獲取詳細信息（約100行）并將其插入mysql數(shù)據(jù)庫。我的問題是，如何在進入下一個項目（城市）之前使函數(shù)在第一個循環(huán)（要獲取城市列表的位置）內等待完成。我想使循環(huán)具有延遲順序。我的源代碼：const request = require('request');var moment = require('moment');var mysql = require('mysql');var a = moment('2019-04-01');var b = moment('2019-04-06');const sleep = (waitTimeInMs) => new Promise(resolve => setTimeout(resolve, waitTimeInMs));function timer(ms) { return new Promise(res => setTimeout(res, ms));}var connection = mysql.createConnection({    host : 'localhost',    user : 'user1',    password : 'password',    database : 'local'});async function getURL(id_city,dates) {    var url = 'https://localhost/api/format/json/schedule/city/'+id_city+'/date/'+dates;        request(url, { json: true }, (err, res, body) => {      if (err) { return console.log(err); }      // console.log(body.status);      var item1 = body.schedule.data.item1;      var item2 = body.schedule.data.item2;      connection.connect();      connection.query('INSERT INTO schedule (city,item1,item2) values ("'+id_city+'","'+task1+'", "'+task2+'")', function (error, results, fields) {         if (error) throw error;      });      // connection.end();        });}async function getDate(id_city){    var end;    for (var m = moment(a); m.isBefore(b); m.add(1, 'days')) {        getURL(id_city,m.format('YYYY-MM-DD'));        await timer(1000); //making delay               }}async function main () {        var url = 'https://localhost/api/format/json/list_city';    connection.connect();    request(url, { json: true }, (err, res, body) => {      if (err) { return console.log(err); }          var list_city = body.city; //this is an array          var counter = 0;          list_city.forEach(function(city){              getDate(city.id, function(){              });//i need this to complete before go to next city          });    });//end request url}main();