Chapter 10: Working with Workers samples

Chapter10/worker-app/fibonacci-worker.js

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+const {
+  Worker,
+  isMainThread,
+  parentPort,
+  workerData,
+} = require("worker_threads");
+
+const n = 10;
+// Fibonacci calculator
+const fibonacci = (n) => {
+  let a = 0, b = 1, next = 1, i = 2;
+  for (i; i <= n; i++) {
+    next = a + b;
+    a = b;
+    b = next;
+  }
+  return next;
+};
+
+if (isMainThread) {
+  // Main thread code
+  const worker = new Worker(__filename, {
+    workerData: n,
+  });
+  worker.on("message", (msg) => {
+    console.log(`The Fibonacci number at position ${n} is ${msg}`);
+  });
+  console.log("...");
+} else {
+  // Worker code
+  parentPort.postMessage(fibonacci(workerData));
+}

Chapter10/worker-app/fibonacci.js

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+const n = 10;
+// Fibonacci calculator
+const fibonacci = (n) => {
+  let a = 0, b = 1, next = 1, i = 2;
+  for (i; i <= n; i++) {
+    next = a + b;
+    a = b;
+    b = next;
+  }
+  console.log(`The Fibonacci number at position ${n} is ${next}`);
+};
+
+fibonacci(n);
+console.log("...");

Chapter10/worker-app/hello-worker.js

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+const {
+  Worker,
+  isMainThread,
+  parentPort,
+  workerData,
+} = require("worker_threads");
+
+if (isMainThread) {
+  // Main thread code
+  const worker = new Worker(__filename, {
+    workerData: "Beth",
+  });
+  worker.on("message", (msg) => {
+    console.log(msg);
+  });
+} else {
+  // Worker code
+  const greeting = `Hello ${workerData}!`;
+  parentPort.postMessage(greeting);
+}