[node] worker threads

const { Worker, isMainThread, parentPort } = require("worker_threads");

if (isMainThread) {
  const worker = new Worker(__filename); // 현재 파일을 worker thread에서 실행시킴
  worker.on("message", (message) => console.log("from worker", message));
  worker.on("exit", () => console.log("worker exit"));
  worker.postMessage("ping");
} else {
  parentPort.on("message", (value) => {
    console.log("from parent", value);
    parentPort.postMessage("pong");
    parentPort.close();
  });
}

// owrner.js
const {
  Worker,
  isMainThread,
  parentPort,
  workerData,
} = require("worker_threads");

const threads = new Set();
threads.add(
  new Worker(__dirname + "/employee1.js", {
    workerData: { number: 999 },
  })
);
threads.add(
  new Worker(__dirname + "/employee2.js", {
    workerData: { number: 666 },
  })
);

for (let worker of threads) {
  worker.on("message", (message) => console.log("from worker", message));
  worker.on("exit", () => {
    threads.delete(worker);
    if (threads.size === 0) {
      console.log("job done! threads.size === ", threads.size);
    }
  });
}

//employee 1
const { workerData, parentPort } = require("worker_threads");

const data = workerData;
console.log("data from 1: ", data); 
parentPort.postMessage(data.number / 3);

// employee 2
const { workerData, parentPort } = require("worker_threads");

const data = workerData;
parentPort.postMessage(data.number / 999);