Update And Return Document In Mongodb

I want to get updated documents. This is my original code and it successfully updates but doesn't return the document.

collection.update({ "code": req.body.code },{$set:  req.body.updatedFields}, function(err, results) {
                        res.send({error: err, affected: results});
                        db.close();
                    });

I used the toArray function, but this gave the error "Cannot use a writeConcern without a provided callback":

collection.update({ "code": req.body.code },{$set:  req.body.updatedFields}).toArray( function(err, results) {
                    res.send({error: err, affected: results});
                    db.close();
                });

Any ideas?

collection.update() will only report the number of documents that were affected to its own callback.

To retrieve the documents while modifying, you can use collection.findOneAndUpdate() instead (formerly .findAndModify()).

collection.findOneAndUpdate(
    { "code": req.body.code },
    { $set: req.body.updatedFields },
    { returnOriginal: false },
    function (err, documents) {
        res.send({ error: err, affected: documents });
        db.close();
    }
);

The returnOriginal option (or new with Mongoose) lets you specify which version of a found document (original [default] or updated) is passed to the callback.

returnOriginal was deprecated in version 3.6. Use returnDocument: "before" | "after" for version 3.6 and later.

---

> Disclaimer: This answer currently refers to the Node.js Driver as of version 3.6. As new versions are released, check their documentation for possibly new deprecation warnings and recommended alternatives.

The solution is to set: {returnOriginal: false}.

collection.findOneAndUpdate(
        whereObj,
        updateObj,
        {returnOriginal: false});

Could not find any way to update many and return the modified records in docs, so I made a workaround.

At least one fault that I can find with below method is, you would not be able to tell if document is modified or already had the value that you are using:

function findAndUpdateMany(filter, updateOptions) {
  return collection.find(filter).project({_id: 1}).toArray()
    .then(function(matchingIds) {
      filter = {_id: {$in: matchingIds}}
      return collection.updateMany(filter, updateOptions)
    }).then(function() {
      return collection.find(filter).toArray()
    })
}

to get the updated doc when performing an update operation on one doc, use findOneAndUpdate() and in the options object, set returnDocument property to 'after'

let options = {returnDocument: 'after'}

const upadatedDoc = collection.findOneAndUpdate({'your query'},{'your update'}, options)

In case you are using mongoose, returnOriginal: false did NOT work for me at v5.11.10,

but new: true worked,

from official mongoose docs:

const filter = { name: 'Jean-Luc Picard' };
const update = { age: 59 };

let doc = await Character.findOneAndUpdate(filter, update, {
  new: true
});
doc.name; // 'Jean-Luc Picard'
doc.age; // 59

Checkout the WriteResult object:

http://docs.mongodb.org/manual/reference/method/db.collection.update/#writeresults-update

WriteResult result = collection.update({ "code": req.body.code },{$set:  req.body.updatedFields}, function(err, results) {
                    res.send({error: err, affected: results});
                    db.close();
                });

result should have something like:

WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

If you want the updated results, do another query with the primary key.