How to fix an MongoClient is not a constructor error

I'm just learning JavaScript and Nodejs, based on some code I found online, I wrote the below application. When I try to run it I get an error on line 9, where it says "new MongoClient". The erroe says that "MongoClient is not a constructor". Could you please explain the issue and how to fix it? Thanks for your responses!

code:

const MongoClient = require('mongodb').MongoClient;
const Server = require('mongodb').Server;

async function main(){
  console.log("Starting main");
  console.error(`error in main`);
  const uri = "mongodb+srv://miniMurali:Snowyndm@cluster0-5jxw4.mongodb.net/test? 
retryWrites=true&w=majority&useUnifiedTopology=true";


  const client = new MongoClient(new Server(uri)); //***error here***
//const mongodb = context.services.get("mongodb-atlas")

//To delete later
//await client.connect();
//await listDatabases(client);

try{

    //await client.connect();
    var MongoClient
    const Booths = client.db("client").collection("booths");
    const Vendors= client.db("client").collection("vendors");
    const db = client.db("client");
    const collections = db.getCollectionNames();

    console.log("Starting DB processing");

    await listDatabases(client);
    await addSampleData(Booths, Vendors);
    await readSampleData(Booths, Vendors);
    await searchBooths(db);
    await deleteData(Booths, Vendors);
} catch (e){
    console.error(e);
}

finally {
    await client.close();
}


//main(). catch(console.error);

}
async function listDatabases(client){
    databasesList = await client.db().admin().listDatabases();
    console.log("Databases:");
    databasesList.databases.forEach(db => console.log(`-${db.name}`));
};



//to be deleted later, sample data in order to add functions that organize it later
async function addSampleData(Booths, Vendors){

    const booth1 = {'number': 1,
     location:"lowerCommons", "outlets":2, size:"10 x 10", "vendorID": "none"}
    let vendor1= {"vendorID": 1, "name": "Doggo", "business": "Puppy", "phone1":"111-111-1111", 
"email": "TennisBall@puppup.net", "phone2":"none", "tables": 3, "boothsAllocated":"yes", 
"addressLine1": "Woof woof", "city": "Slobberton", "state":"fluff"}
await Booths.insertOne(booth1)
.then(result => console.log(`Successfully inserted item with _id: ${result.insertedId}`))
.catch(err => console.error(`Failed to insert item: ${err}`));

await Vendors.insertOne(vendor1)
.then(result => console.log(`Successfully inserted item with _id: ${result.insertedId}`))
.catch(err => console.error(`Failed to insert item: ${err}`))
}


async function readSampleData(Booths, Vendors){

    var boothsA= new Array;
    boothsA.push(Booths);

    var vendorsA=new Array;
    vendorsA.push(Vendors);




        //boothsA.find(searchBooths);
}      

function searchBooths(db){

     collections = db.getCollectionNames();
    for(var i = 0; i< collections.length; i++){    
    print('Collection: ' + collections[i]); // print the name of each collection
    db.getCollection(collections[i]).find().forEach(printjson);
    } //and then print the json of each of its elements/

}

 function deleteData(Booths, Vendors){
    console.log('Booths');
}

main(). catch(console.log);

Error details:

Starting main
error in main
TypeError: MongoClient is not a constructor
  at main (C:\Users\nishu\OneDrive\Documents\GitHub\craft-fair-app\Nisha\app2.js:10:17)
  at Object.<anonymous> (C:\Users\nishu\OneDrive\Documents\GitHub\craft-fair-app\Nisha\app2.js:97:2)
  at Module._compile (internal/modules/cjs/loader.js:1157:30)
  at Object.Module._extensions..js (internal/modules/cjs/loader.js:1177:10)
  at Module.load (internal/modules/cjs/loader.js:1001:32)
  at Function.Module._load (internal/modules/cjs/loader.js:900:14)
  at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:74:12)
  at internal/main/run_main_module.js:18:47