added threads in js post

src/pages/posts/Threaded-js.md

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+---
+layout: '../../layouts/post.astro'
+title: 'Threaded JavaScript!'
+---
+
+# Threaded Javascript
+
+For a long time, my language of choice has been JavaScript (and recently TypeScript), this is for both frontend development as well as backend development. 
+
+I enjoy the simplicity of using the same language for both sides of a project and I especially like working with Node.js, a Javascript run time environment with a very sophisticated asynchronous event loop, which makes it perfect for applications such as RESTful APIs which access databases etc...
+
+However, I have also done backend work using Golang, a strongly typed, compiled, very fast language with a vibrant community and a "do it yourself" attitude, quite the change from Javascript. And something I have touched and enjoyed playing with are go routines, which are a way to create very light weight threads. This works by calling a function as a "go routine", which I think is very elegant. This is managed by the go run-time environment, but it can spawn threads if it needs to - a nice abstraction which means I don't have to handle threads directly - but do have to handle go routines as if they ARE threads.
+
+But anyways, it left me wondering if I could have threads in JavaScript, which sounds crazy but Node.js has support for this is "Worker Threads". These are threads managed by Node.js which can run a .js file and communicate with its parent - it is quite similar to go routines.
+
+So I made a small program to calculate the same MD5 hash 1 million times:
+
+(Note that these files are .mjs files (module JavaScript), Node.js will only run them if you have .mjs as the file extension - All they do is allow the "import" syntax and a few other things).
+
+```js
+import crypto from 'crypto';
+
+console.time("Single-Thread");
+
+const n = 10000000;
+const string = "Hello World";
+
+for (let i = 0; i < n; i++) {
+  const hash = crypto.createHash('md5').update(string).digest('hex');
+}
+
+console.timeEnd("Single-Thread");
+
+```
+
+Running this program gave me this result:
+```
+Single-Thread: 1.139s
+```
+
+I then modified my code to use worker threads. This splits the work load into 8 worker threads, it gives each thread a start and an end range for the hash - which in total makes 1 million hashes.
+
+```js
+import { fileURLToPath } from 'url';
+import { Worker, isMainThread, parentPort, workerData } from 'worker_threads';
+import crypto from 'crypto';
+
+const __filename = fileURLToPath(import.meta.url);
+const n = 1000000;
+const THREAD_NUM = 8;
+const string = "Hello World";
+
+if (isMainThread) {
+  
+  const threads = new Set();
+  for (let i = 0; i < THREAD_NUM; i++) {
+    threads.add(new Worker(__filename, {workerData: {
+      start: i * (n / THREAD_NUM), 
+      end: (i * (n / THREAD_NUM)) + n / THREAD_NUM} 
+    }))
+  }
+
+  console.time("Thread");
+  
+  for (const worker of threads) {
+    worker.on('message', msg => console.log(msg));
+    worker.on('exit', () => {
+      threads.delete(worker);
+      if (threads.size === 0) {
+        console.timeEnd("Thread");
+      } 
+    });
+  }
+
+} else {
+  
+  for (let i = workerData.start; i < workerData.end; i++) {
+    const hash = crypto.createHash('md5').update(string).digest('hex');
+  }
+  
+  parentPort.postMessage('Done!');
+}
+
+```
+
+This results in the following output:
+
+```js
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Thread: 335.294ms
+```
+
+A 4x increase in speed. There is a delay because worker threads actually spawn threads and therefore there is a bit of overhead with the syscall to create these threads.
+
+This is very clear if we changed the number of hashes to 10 000.
+
+### Single Thread
+```
+Single-Thread: 23.476ms
+```
+
+### 8 Worker Threads
+```
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Done!  
+Thread: 70.337ms
+```
+
+As you can see the single thread beat the 8 threads by almost 4x. This is because it is costly to create a thread outright which is what Node.js seems to be doing.
+
+## Disclaimer
+The Node.js crypto module is basically a wrapper for the native OpenSSL hashing functions, so I suspect that Node.js is just making a very fast C program do the hard work - but never the less it works very well.
+
+
+## Conclusion
+Node.js is a very solid backend technology to perform parallalism, it is not just limited to making RESTful APIs. It can competes with strongly typed and compiled languages such as golang.