Nodejs workers as writeable stream

boss.js

'use strict';
/**
 * Nodejs Stream Workers example
 *  will cipher and return deciphered file.txt to console output
 *  using a worker as a writeable stream.
 *
 * Use:
 *  node boss.js < file.txt
 *
 * if node < 12
 *  node --experimental-worker boss.js < file.txt
 *
 * will cipher file.txt and return deciphered to console :)
 */
const { Worker } = require('worker_threads');

// stdin: true will make worker become a stream
const worker = new Worker('./worker.js', {stdin: true});

//pipe to worker
process.stdin.pipe(worker.stdin);

worker.js

'use strict';
//all sync mode it's a worker it wont block the loop
const crypto = require('crypto');
const key = 'rxSy6ImrMS5hyPU6pg7x3aR4ILxNkuWITNCUe4QALQw=';
let iv = crypto.randomBytes(16);

const createCipheriv = (alg, key) => {
    return crypto.createCipheriv(alg, Buffer.from(key, 'base64'), iv);
};

const createDecipherIv = (alg, key) => {
    return crypto.createDecipheriv(alg, Buffer.from(key, 'base64'), iv);
};

process.stdin
    .pipe(createCipheriv('aes-256-cbc', key))
    .pipe(createDecipherIv('aes-256-cbc', key))
    .pipe(process.stdout);