jthomas · April 10, 2022 13:22 · May 8, 2019 · May 8, 2019
diff --git a/package.json b/package.json
@@ -1,12 +0,0 @@
-{
-  "name": "worker_threads",
-  "version": "1.0.0",
-  "description": "",
-  "main": "primes-with-workers.js",
-  "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1"
-  },
-  "keywords": [],
-  "author": "James Thomas <[email protected]> (https://jamesthom.as)",
-  "license": "MIT"
-}

diff --git a/package.json b/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "worker_threads",
+  "version": "1.0.0",
+  "description": "",
+  "main": "primes-with-workers.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "James Thomas <[email protected]> (https://jamesthom.as)",
+  "license": "MIT"
+}
diff --git a/primes-with-workers.js b/primes-with-workers.js
@@ -0,0 +1,41 @@
+'use strict';
+
+const { Worker } = require('worker_threads');
+const os = require('os')
+const threadCount = os.cpus().length
+
+const compute_primes = async (start, range) => {
+  return new Promise((resolve, reject) => {
+    let primes = []
+    console.log(`adding worker (${start} => ${start + range})`)
+    const worker = new Worker('./worker.js', { workerData: { start, range }})
+
+    worker.on('error', reject)
+    worker.on('exit', () => resolve(primes))
+    worker.on('message', msg => {
+      primes = primes.concat(msg)
+    })
+  })
+}
+
+async function main(params) {
+  const { min, max } = params
+  const range = Math.ceil((max - min) / threadCount)
+  let start = min < 2 ? 2 : min
+  const workers = []
+
+  console.log(`Calculating primes with ${threadCount} threads...`);
+
+  for (let i = 0; i < threadCount - 1; i++) {
+    const myStart = start
+    workers.push(compute_primes(myStart, range))
+    start += range
+  }
+
+  workers.push(compute_primes(start, max - start))
+
+  const primes = await Promise.all(workers)
+  return { primes: primes.flat() }
+}
+
+exports.main = main
diff --git a/primes.js b/primes.js
@@ -0,0 +1,24 @@
+'use strict';
+
+const min = 2
+
+function main(params) {
+  const { start, end } = params
+  console.log(params)
+  const primes = []
+  let isPrime = true;
+  for (let i = start; i < end; i++) {
+    for (let j = min; j < Math.sqrt(end); j++) {
+      if (i !== j && i%j === 0) {
+        isPrime = false;
+        break;
+      }
+    }
+    if (isPrime) {
+      primes.push(i);
+    }
+    isPrime = true;
+  }
+
+  return { primes }
+}
diff --git a/workers.js b/workers.js
@@ -0,0 +1,27 @@
+'use strict';
+const { Worker, isMainThread, parentPort, workerData } = require('worker_threads');
+
+const min = 2
+
+function generatePrimes(start, range) {
+  const primes = []
+  let isPrime = true;
+  let end = start + range;
+  for (let i = start; i < end; i++) {
+    for (let j = min; j < Math.sqrt(end); j++) {
+      if (i !== j && i%j === 0) {
+        isPrime = false;
+        break;
+      }
+    }
+    if (isPrime) {
+      primes.push(i);
+    }
+    isPrime = true;
+  }
+
+  return primes
+}
+
+const primes = generatePrimes(workerData.start, workerData.range);
+parentPort.postMessage(primes)