A quick snippet that can be used to upload a file to an S3 bucket.

s3Helper.js

const AWS = require('aws-sdk');

function putObjectToS3(bucket, key, data){
    return new Promise((resolve, reject) => {
        let s3 = new AWS.S3();
        var params = {
            Bucket : bucket,
            Key : key,
            Body : data
        }
        s3.putObject(params, function(err, data) {
            if (err) {
                reject(err);
            } else {
                resolve(data);
            }
        });
    })
}