generate report on a mongodb collection using nodejs

mongo-db-cursor-example.js

const mongoose = require('mongoose')
const util = require('util')
const stream = require('stream')
const pipeline = util.promisify(stream.pipeline)
const stringify = require('csv-stringify')
const fs = require('fs')
const fsp = require('fs').promises

let schema = mongoose.Schema({
    name:String,
    email:String,
    gender:String,
    active:{type:Boolean,default:true},
});
let User=mongoose.model('user',schema);

async function generateReport(){
    //create query cursor
    let  usersCursor= User.find({active:true}).cursor({transform:(user)=>{        
        let {_id:userId,email,gender}= user.toObject()
        return {userId,email,gender}
    }})
    //create object to csv transformer
    let csvStream = stringify({
            header: true,
            columns: {
               userId: 'USER_ID',
               email:'EMAIL',
               gender: 'GENDER',
            }
        })        
    //create a file sink
    let dst = `./report.csv`
    await pipeline(usersCursor,csvStream,fs.createWriteStream(dst))
    console.log('report generated')
}

mongoose.connect('mongodb://localhost:27017/test_db', { useNewUrlParser: true, reconnectTries: Number.MAX_VALUE  }, function(err) {
  if (err) {
      console.error( 'Couldnt connect to MongoDB:', err);
  } else {
    console.log('Connected to MongoDB');
    generateReport()
  }
});