Multithreading in Node.js
On Node.js version 13, a new module called worker threads is there to implement multithreading.
In the index.js (main thread) we will use two routes and a function that returns the cumulative sum up to the limit value given as an argument.
const getSum = (limit) => {
let sum = 0;
for (let i = 0; i < limit; i++) { sum += i; }
return sum;
};
app.get("/", (req, res) => {
res.send("Process function on main thread.");
});
app.get("/seprate-thread", (req, res) => {
res.send("Process function on seprate thread.");
});
And then we import the worker thread module to the main thread, and create another file seprateThread.js for defining the function getSum to run on another thread
const { Worker } = require("worker_threads");
To create an instance of the worker thread module and provide the pathname to the newly created file, it will be like that.
const seprateThread = new Worker(__dirname + "/seprateThread.js");
To start the new thread
seprateThread.on("message", (result) => {
res.send(`Processed function getSum on seprate thread: ${result}`);
});
To send data to the new thread
seprateThread.postMessage(1000);
parentPort.postMessage() used by the child thread (seprateThread.js) to communicate with the main thread. The below figure illustrates the communication between the child and the main thread.