MongoDB get the number of documents (count) in a collection using Node.js

Question

I\'m currently writing a function that should return the number of documents from a collection the thing is that when i\'m returning the value it says undefined, Here is my

Answer 1

The use of count() is deprecated since mongodb 4.0.

Instead you should use documentCount() alternative, but is much moere slower than count() with large ammounts of data.

The alternatives are estimatedDocumentCount() that performs quite well and the usage is:

var MongoClient = require('mongodb').MongoClient;

var dbName = "ystocks";
var port = "27017";
var host = "localhost";

function getNumOfDocs (collectionName, host, port, dbName, callback) {
    MongoClient.connect("mongodb://" + host + ":" + port + "/" + dbName, function (error, db){
        if(error) return callback(error);

        db.collection(collectionName).estimatedDocumentCount({}, function(error, numOfDocs){
            if(error) return callback(error);

            db.close();
            callback(null, numOfDocs);
        });
    }); 
} 

Another option I use is to get the number of documents from the collection stats:

var MongoClient = require('mongodb').MongoClient;

var dbName = "ystocks";
var port = "27017";
var host = "localhost";

function getNumOfDocs (collectionName, host, port, dbName, callback) {
    MongoClient.connect("mongodb://" + host + ":" + port + "/" + dbName, function (error, db){
        if(error) return callback(error);

        db.collection(collectionName).stats(function(error, stats){
            if(error) return callback(error);

            db.close();
            callback(null, stats.count);
        });
    }); 
}