mongodb.js

var mongodb = require('mongodb');
// var MongoClient = mongodb.MongoClient; var ObjectID = mongodb.ObjectID;
var {MongoClient, ObjectID} = require('mongodb');

var connectionURL = 'mongodb://127.0.0.1:27017';
var databaseName = 'task-manager';

var id = new ObjectID();
console.log(id.getTimestamp());

MongoClient.connect(connectionURL,{useNewUrlParser:true, useUnifiedTopology: true},(error, client)=>{
    if(error){
        return console.log("Unable to connect");
    }

    //The database that we are trying to maniplulate
    const db = client.db(databaseName);

    var updatePromise = db.collection('users').deleteMany({
        age:20
    });

    updatePromise.then((result)=>{
        console.log(result.deletedCount);
    }).catch((err)=>{
        console.log(err);
    });
});