How to transfer Postgres Data from Query to S3 Efficiently

This should get you ~90% there. I haven't tested this exact implementation and there may be a typo or two, but I have similar code running in production right now.

const { Transform } = require('json2csv');const { Client, Query } = require('pg')const { S3 } = require('aws-sdk');const { Passthrough } = require('stream')const client = new Client()const s3 = new S3({ region: 'us-east-1' });const opts = { fields: ['field1', 'field2', 'field3'] };const transformOpts = { highWaterMark: 8192, encoding: 'utf-8', objectMode: true };const transform = new Transform(opts, transformOpts);const passthrough = new Passthrough();transform.pipe(passthrough)client.connect()const query = new Query('SELECT field1, field2, field3 FROM table')client.query(query)query.on('row', row => {  transform.push(row);  console.log('row!', row) // { field1: 1, field2: 2, field3: 3 }})query.on('end', () => {  transform.push(null)  console.log('query done')})query.on('error', err => {  transform.end();  console.error(err.stack)})s3.upload({ Body: passthrough, Key: 'somefile.csv', Bucket: 'some_bucket' }).send((err, data) => {  if (err) {    console.error({ err });    passthrough.destroy(err);  } else {    console.log(`File uploaded and available at ${data.Location}`);    passthrough.destroy();  }});