index.js

const { Worker } = require('worker_threads');
const path = require('path');

const buffer = new SharedArrayBuffer(1);

const worker = new Worker(path.resolve('./worker.js'));
worker.on('message', () => {
  // check buffer was changed ?
  const int8Array = new Int8Array(buffer);
  console.log(`main thread buffer: ${int8Array[0]}`)
});
worker.postMessage(buffer);