Koa2 uses mongodb to write api interface to get data, how to get data elegantly (I am adding data to a new object, it's too low)

const MongoClient = require("mongodb").MongoClient;
const url = "mongodb://localhost:27017";
// Database Name
const dbName = "youyue";
var obj = {};
module.exports = async(ctx,next)=>{ 

    const num = ctx.query.num,
        page = ctx.query.page,
        sort = ctx.query.sort;

    num = isNaN(num)? 10 : parseFloat(ctx.query.num)
    page = isNaN(page)?0 : parseFloat(ctx.query.page)
    sort = isNaN(sort)?-1 : parseFloat(ctx.query.sort)
       
    console.log(num+"*"+sort+"*"+page);
    MongoClient.connect(url, function (err, client) {
        const db = client.db(dbName);
        const collection = db.collection("site");
        collection.find().sort({ id: sort  }).skip(num*page).limit(num).toArray(function (err, Database){
            console.log(Database);
            //
            obj.result = Database;
        });
    });
    await next(); 
    //
    ctx.body = obj.result;
}

Node.js mongodb javascript koa2

Mar.03,2021

write the query Mongodb paragraph as a function, function return promise. Then call this function and do not low.

function queryToDB(url){
  return new Promise(function(resolve, reject){
    MongoClient.connect(url, function (err, client) {
    const db = client.db(dbName);
    const collection = db.collection('site');
    collection.find().sort({ id: sort  }).skip(num*page).limit(num).toArray(function (err, Database){
        if(err) reject(err);
        else resolve(Database)
    });
});
    

queryToDB(url).then(function(result){
  if(result && result.length > 0){
    ctx.body = result;
  }
}).catch(function(ex){
   // Todo:
});

elegant advice

change MongoClient.connect with util.promisify to promise and use await to wait for the link to succeed.
persist data links and do not link to the database every time you request it.
write const collection = db.collection ('site'); as a class pattern Site.find .
similarly write Site.find as await .

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bea656-30f3b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bea656-30f3b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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