Concurrency and Multithreading in MERN Stack Applications

In the context of MERN stack applications, concurrency refers to the ability to execute multiple tasks simultaneously. Multithreading, on the other hand, involves dividing a program into multiple threads that can run concurrently.

JavaScript, as a single-threaded language, has a single call stack that executes tasks synchronously. However, MERN stack applications can still achieve concurrency and multithreading through various approaches.

Web Workers

Web Workers are a browser feature that enables concurrent execution of JavaScript code in the background. They allow offloading time-consuming tasks to separate threads, keeping the main thread responsive. In MERN stack applications, Web Workers can be used to perform computationally intensive operations on the client-side.

Here's an example of using Web Workers to perform concurrent increment and decrement operations on a shared variable:

1// Main thread
2const count = 0;
3
4function increment() {
5  for (let i = 0; i < 1000; i++) {
6    count++;
7  }
8}
9
10function decrement() {
11  for (let i = 0; i < 1000; i++) {
12    count--;
13  }
14}
15
16// Create two threads to simulate concurrent execution
17const worker1 = new Worker(increment);
18const worker2 = new Worker(decrement);
19
20// Start the workers
21worker1.start();
22worker2.start();

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const count = 0;

​

function increment() {

  for (let i = 0; i < 1000; i++) {

    count++;

  }

}

​

function decrement() {

  for (let i = 0; i < 1000; i++) {

    count--;

  }

}

​

// Create two threads to simulate concurrent execution

const thread1 = new Thread(increment);

const thread2 = new Thread(decrement);

​

// Start the threads

thread1.start();

thread2.start();