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

// 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); 
})