Update And Return Document In Mongodb

Question

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?

Answer 1

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

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

Answer 2

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.

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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.