Mongoose: findOneAndUpdate doesn't return updated document

Below is my code

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test');

var Cat = mongoose.model('Cat', {
    name: String,
    age: {type: Number, default: 20},
    create: {type: Date, default: Date.now} 
});

Cat.findOneAndUpdate({age: 17}, {$set:{name:"Naomi"}},function(err, doc){
    if(err){
        console.log("Something wrong when updating data!");
    }

    console.log(doc);
});

I already have some record in my mongo database and I would like to run this code to update name for which age is 17 and then print result out in the end of code.

However, why I still get same result from console(not the modified name) but when I go to mongo db command line and type "db.cats.find();". The result came with modified name.

Then I go back to run this code again and the result is modified.

My question is: If the data was modified, then why I still got original data at first time when console.log it.

Solution 1:

Why this happens?

The default is to return the original, unaltered document. If you want the new, updated document to be returned you have to pass an additional argument: an object with the new property set to true.

From the mongoose docs:

Query#findOneAndUpdate
Model.findOneAndUpdate(conditions, update, options, (error, doc) => {
  // error: any errors that occurred
  // doc: the document before updates are applied if `new: false`, or after updates if `new = true`
});
Available options

new: bool - if true, return the modified document rather than the original. defaults to false (changed in 4.0)

Solution

Pass {new: true} if you want the updated result in the doc variable:

//                                                         V--- THIS WAS ADDED
Cat.findOneAndUpdate({age: 17}, {$set:{name:"Naomi"}}, {new: true}, (err, doc) => {
    if (err) {
        console.log("Something wrong when updating data!");
    }

    console.log(doc);
});

Solution 2:

For anyone using the Node.js driver instead of Mongoose, you'll want to use {returnOriginal:false} instead of {new:true}.

2021 - Mongodb ^4.2.0 Update
{ returnDocument: 'after' }

Solution 3:

So, "findOneAndUpdate" requires an option to return original document. And, the option is:

MongoDB shell

{returnNewDocument: true}

Ref: https://docs.mongodb.com/manual/reference/method/db.collection.findOneAndUpdate/

Mongoose

{new: true}

Ref: http://mongoosejs.com/docs/api.html#query_Query-findOneAndUpdate

Node.js MongoDB Driver API:

{returnOriginal: false}

2021 - Mongodb ^4.2.0 Update
{ returnDocument: 'after' }

Ref: http://mongodb.github.io/node-mongodb-native/3.0/api/Collection.html#findOneAndUpdate

Solution 4:

By default findOneAndUpdate returns the original document. If you want it to return the modified document pass an options object { new: true } to the function:

Cat.findOneAndUpdate({ age: 17 }, { $set: { name: "Naomi" } }, { new: true }, function(err, doc) {

});

Solution 5:

For whoever stumbled across this using ES6 / ES7 style with native promises, here is a pattern you can adopt...

const user = { id: 1, name: "Fart Face 3rd"};
const userUpdate = { name: "Pizza Face" };

try {
    user = await new Promise( ( resolve, reject ) => {
        User.update( { _id: user.id }, userUpdate, { upsert: true, new: true }, ( error, obj ) => {
            if( error ) {
                console.error( JSON.stringify( error ) );
                return reject( error );
            }

            resolve( obj );
        });
    })
} catch( error ) { /* set the world on fire */ }