Node.js snippet that converts an AWS IAM secret access key to an AWS SES SMTP password

aws_ses_iam_to_smpt_password.js

/*
 * Implementation of the algorithm described here:
 * https://docs.aws.amazon.com/ses/latest/DeveloperGuide/smtp-credentials.html
 */

const {createHmac} = require("crypto");

const key = process.env.KEY || (() => { throw new Error("Variable KEY not defined")} )();
const msg = "SendRawEmail";
const version = new Buffer(1);
version.writeUInt8(0x02, 0);
const signature = createHmac("sha256", key).update(msg).digest();
const signatureAndVer = Buffer.concat([version, signature]);

console.log(signatureAndVer.toString("base64"));