What are Web Workers and why are they necessary

Web Workers are a JavaScript feature that allows creating new threads without interfering with the main UI thread (which has full responsibility for the page displayed on the screen). This technology helps optimize computer resources by allowing heavy tasks such as calculations, data analysis, or file processing to be performed without degrading the user experience.

Why Web Workers are important

High-performance applications often require extensive calculations or long-running operations that can degrade the user interface by slowing it down. In other words, when large amounts of data or calculations are being processed, the UI becomes unresponsive and slow, which hinders the user experience. Web Workers help solve this problem by performing these tasks in separate threads without affecting the UI.

When to use Web Workers

• CPU-intensive tasks - Complex algorithms, data processing, and similar functions that can slow down the system.
• Heavy calculations - Generally resource-intensive functions that take considerable time, such as mathematical or complex analyses.
• Keeping the UI responsive - To ensure your application remains fast and easy to use, Web Workers allow the UI to work without interruption.

How Web Workers work

A Web Worker runs in a separate thread, meaning it doesn't occupy the main thread responsible for the UI. Thus, when a Web Worker performs heavy operations, the UI doesn't slow down and the user can continue working with other functions.

For security reasons, Web Workers don't have access to the main DOM. Therefore, if you want to modify the DOM, you need to send a message directly from the Worker to the Main thread to receive a response.

Example: Creating a Web Worker

  
// main.js (Main Thread)
const worker = new Worker('worker.js');  // Creating the Worker

worker.postMessage('Hello, Worker!');  // Sending a message to the Worker

worker.onmessage = function(e) {
  console.log('Main thread received:', e.data);  // Receiving a response from the Worker
};

  
// worker.js (Web Worker)
onmessage = function(e) {
  console.log('Main thread says:', e.data);  // Reading the message received from the Main thread
  postMessage('Hello from Worker!');  // Sending a response back to the Main thread
};

Advantages of Web Workers

• Optimization - Web Workers allow performing heavy calculations without affecting the UI.
• Responsiveness - The UI always remains responsive and allows normal user interaction.
• High performance - Web Workers can perform heavy and extensive calculations without disrupting the main thread's work.

Conclusion

Using Web Workers is an important step in optimizing our application's performance, especially when working with heavy data or when complex computational operations are required. This is why Web Workers are very useful in modern applications - they ensure a good user experience despite the performance of heavy tasks.