How to get last record's one value in mongoose

user_13031268 0
Viewed 5567

Tried to get last record value one but not working. How to do it in mongoose.

Sample data records in mongodb:

[
    {
        _id: 5f0c73f69b34214310d0acee,
        name: "Test",
        age: 28,
        voice: "Not Tested"
    },
    {
        _id: 5f0c73f69b34214310d0akke,
        name: "Test2",
        age: 38,
        voice: "Tested"
    }
]

Mongoose query:

The value of voice property in the last record is "Tested" so I tried to get that value.

var Order = mongoose.model(collectionName);
  Order.find({}).sort({ _id: -1 }).limit(1).then((products) => {
    
    products.findOne({voice}, function(err,obj) { 
    
      console.log(obj);//Output should be = Tested
    
    });
});
mongoose node.js mongodb
3 Answers

Finally, after trying for long 3 hours I found the answer.

    User.find({}).sort({_id: -1}).limit(1).then((products) => {
        console.log(products[0].voice)
    })
user_138774220

Because you doing it wrong. Actually if you needed not last inserted in a collection document, but last updated you should use timestamps in your schema (mongoose docs)

So you collection schema should be something like this:

let schema = new mongoose.Schema({
    field_one: Number,
    field_two: String,
},{
    timestamps: true
});

So you will have not just field_one and field_two, but also special fields like createdAt and updatedAt

Then, don't forget to add index for performance at you schema on updatedAt field, like this:

schema.index({ updatedAt: -1 },{name: 'IndexName'});

and only them use:

async function LastUpdatedVoice () {
   try {
       let t = await model.findOne({ "field_one": "value" }).select('voice').lean().sort({updatedAt: -1});
       console.log(t);
   } catch (e) {
       console.error(e)
   }
}

For last inserted document the code will be the same, but instead of updatedAt field, you should use createdAt field.

Also, one more thing:

*If you need to updated this document right after it has been found, you could do it without using lean() option in my query. And updated the Mongoose Doc itself, via:

t.voice = new_value
t.save()

but I highly recommend you to use findOneAndUpdate method them.

user_74756150

I found it simpler this way.

let lastDoc = (await Model.find({}).sort({_id: -1}).limit(1))[0];
console.log(lastDoc);

Otherwise, if you use it inside a function, make sure the function is async.

let docHandler = async () => {
   let lastDoc = (await Model.find({}).sort({_id: -1}).limit(1))[0];
   console.log(lastDoc);
};
user_136077670
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