How to count total number of unique documents in MongoDB using Node.js ?

Last Updated : 12 Feb, 2021

MongoDB, the most popular NoSQL database, we can count the number of documents in MongoDB Collection using the MongoDB collection.countDocuments() function. The mongodb module is used for connecting the MongoDB database as well as used for manipulating the collections and databases in MongoDB.

Installing module: You can install mongodb module using the following command.

npm install mongodb

Project Structure:

Running the server on Local IP: Data is the directory where MongoDB server is present.

mongod --dbpath=data --bind_ip 127.0.0.1

MongoDB Database:

Database:GFG
Collection:aayush

Following is the sample data stored in your database for this example.

Filename: index.js

JavaScript

// Requiring module
const MongoClient = require("mongodb"); 

// Connection URL
const url = 'mongodb://localhost:27017/'; 

// Database name 
const databasename = "GFG";
 
MongoClient.connect(url).then((client) => { 
  const connect = client.db(databasename); 

  // Connect to collection 
  const collection = connect.collection("aayush"); 

  // Counting the total unique documents
  collection.distinct("name").then((ans) => {
    // Creating set
    var set1 = new Set();

    // Adding each element in the st    
    ans.forEach(i => {
      set1.add(i);  
    });

    // Printing the size of the set
    console.log(set1.size);
  }).catch((err)=>{
      console.log(err.Message);
  })  
}).catch((err) => { 

  // Printing the error message 
  console.log(err.Message); 
})