How to correctly update the field?

Question

JavaScript

When uploading files, an out-of-sequence occurs, causing the file name to not update correctly and the collection field filenameto remain empty.

const router = require('express').Router();
const mongoose = require("mongoose");
const multer = require('multer');
const aws = require('aws-sdk');
const multerS3 = require('multer-s3');
const Collection = require("../models/ts");

aws.config.update({
    secretAccessKey: process.env.ACCESS_KEY,
    accessKeyId: process.env.ACCESS_KEY_ID,
    region: process.env.REGION
});

const s3 = new aws.S3();
const upload = multer({
    storage: multerS3({
        s3: s3,
        bucket: 'site.com',
        acl: 'public-read',
        key: function (req, file, cb) {
          cb(null, path);
          
           Collection.update({ vid: req.body.vid }, { $set: {
            filename: file.originalname,
            } })
      .exec()
      .then(result => {
        console.log('Название файла успешно сохранено');
        })
      .catch(err => {
        console.log(err);
      });
          }
      })
}).any();

router.post("/", upload,(req, res, next) => {
switch(req.body.cs) {

case "addCollection":
 
  const ts = new Collection({
   _id: new mongoose.Types.ObjectId(),
   vid: req.body.vid,	
   filename: ''
  });
  
  ts.save()
  .then(result => {
    if(result){
    console.log('Данные успешно записан в коллекцию');
  } else {
    console.log('Данные в коллекцию не записаны');
  }
  })
  .catch(err => {
        console.log('Ошибка записи в коллекцию');
    });

  res.status(200).json({
    "result":"ok",
  });
  break;

case "addFilename":
  upload(req, res, function (err) {

      if(err) {
        console.log('Ошибка загрузки файлов');
        res.status(500).json({
          Error: "Ошибка загрузки файлов"
        });
        }

        res.status(200).json({
          "result":"ok",
        });
      });
  break;
}
});

In a nutshell, in addCollection the fields are saved, with the filename field still empty, and in addFilename we already get the file itself and update filename with its name.
As a result of the code above, we get the following in the console:

Название файла успешно сохранено
Данные успешно записан в коллекцию

It follows that the update of the filename field occurs before the entry itself actually appears in the collection.
Please help me handle this situation.

Answer 1

Here is your code that reports that an entry has been added to the collection:

res.status(200).json({
    "result":"ok",
  });
  break;

However, this message is false, because this code is not called in the chain of the promise to add the file. Accordingly, you need to write like this:

ts.save()
  .then(result => {
    if(result){
    console.log('Данные успешно записан в коллекцию');
      res.status(200).json({
        "result":"ok",
       });
  } else {
    console.log('Данные в коллекцию не записаны');
  }
  })
  .catch(err => {
        console.log('Ошибка записи в коллекцию');
    });