Is this a good solution to when updating nested objects?

[MarkWilliamsDev]

I've been struggling all evening with the issue where updating one key in a nested object causes all values to be overwritten. After loads of research looking for a simple solution, I tried something out where, as far as I understand it, any keys that don't receive a new value will update the new instance with the existing data.

 `const {
  name,
  venueContact,
  line1,
  line2,
  city,
  county,
  postCode,
  country,
  _id
} = req.body

try {
  const venue = await Venue.findById(_id)
  venue.name = name
  venue.venueContact = venueContact
  venue.address.line1 = line1 || venue.address.line1
  venue.address.line2 = line2 || venue.address.line2
  venue.address.city = city || venue.address.city
  venue.address.county = county || venue.address.county
  venue.address.postCode = postCode || venue.address.postCode
  venue.address.country = country || venue.address.country
  venue.save()

  res.send(venue)
} catch (err) {

  res.send(err)
}`

It seems to work but am I missing something that could become an issue?

[AndrewFriendTech]

If you have a rapidly updating database, you could cause race conditions where multiple clients are updating the same code at once and end up with garbled objects if one user submits the change after another user has downloaded the object, but before his client has submitted it.

For your situation , it is probally best to use Venue.Update() queries. See here in the mongoose docs.

Sorry for replying so late to your post, i don't normally browse the discussions of here, you might find stack overflow will give you faster answer. (but they can tend to be rude at times as well)

[AbdelrahmanHafez]

@AndrewFriendTech Document#save(...) uses Model.updateOne(...)/Model.insertOne(...) under the hood, you have a point regarding the race condition though, he needs to await on venu.save() to avoid some race-conditions.

[AbdelrahmanHafez]

That does work, but that seems to be too much repetition and that's an anti-pattern.
You seem to want to set an item if it's present in req.body.
A different approach would be to build a clean utility that removes any null or undefined properties from req.body and document.set(req.body); then document.save();

try {
  const venue = await Venue.findById(_id);

  clean(req.body);
  revenue.set(req.body);

  await venue.save();

  return  res.send(venue);
} catch (err) {
  res.send(err)
}

function clean(obj) {
  for (const propName in obj) {
    // technically, you'd need to do `!obj[propName]` to have the equivalent implementation
   // of what you have in the original post
    if (obj[propName] == null) { 
      delete obj[propName];
    }
  }

Also, as @AndrewFriendTech has mentioned, you want to await venue.save(); to be over, so that if an error happened, you'd notify the user with it instead of assuming that the save will just work.

One more thing I'd do with the changes above is validate the req.body using joi to avoid malicious users sending more information (for example venue.size) than intended which will eventually go to the database.