Simple example of uploading to S3 from the filesystem with Node.js - If you're trying to learn how to do this, checkout Fullstack Node.js https://newline.co/fullstack-nodejs

s3-upload-node.js

const fs = require('fs')
const AWS = require('aws-sdk')
const { promisify } = require('util')
const s3 = new AWS.S3()
s3.uploadP = promisify(s3.upload)
const params = {
  Bucket: 'fullstack-printshop',
  Key: 'profile-photos/thedude.jpg',
  Body: fs.createReadStream('thedude.jpg')
}
(async function () {
  await s3.uploadP(params)
})()