Web workers for heavy computation in Angular - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of using Web Workers in Angular?

Web Workers allow Angular apps to run heavy computations in the background without freezing the user interface, keeping the app responsive.

beginner

How do you create a Web Worker in Angular?

Use the Angular CLI command ng generate web-worker <worker-name> to create a worker file and integrate it properly.

intermediate

How does communication happen between the main Angular thread and a Web Worker?

Communication happens by sending messages back and forth using postMessage() and listening with onmessage handlers.

beginner

Why should heavy computation be offloaded to Web Workers in Angular apps?

Heavy computation blocks the main thread, causing UI freezes. Web Workers run in a separate thread, keeping the UI smooth and responsive.

intermediate

Can Web Workers access the DOM directly in Angular?

No, Web Workers cannot access the DOM directly. They run in a separate thread and communicate with the main thread to update the UI.

What Angular CLI command creates a new Web Worker?

A ng generate web-worker worker-name

B ng create worker worker-name

C ng add web-worker worker-name

D ng build worker worker-name

The correct command is ng generate web-worker worker-name to create a Web Worker in Angular.

Which method is used to send data from the main thread to a Web Worker?

A sendMessage()

B dispatchMessage()

C emit()

D postMessage()

The postMessage() method sends data to a Web Worker.

Why can't Web Workers access the DOM directly?

A They run in a separate thread without DOM access

B They lack permission from Angular

C They only run on the server

D They are disabled by default

Web Workers run in a separate thread and do not have access to the DOM to avoid conflicts and keep UI safe.

What is the main benefit of using Web Workers in Angular apps?

A Faster HTTP requests

B Improved UI responsiveness during heavy tasks

C Automatic memory management

D Simpler code syntax

Web Workers keep the UI responsive by running heavy tasks in the background.

How does the main thread receive messages from a Web Worker?

A Using listen() method

B Using getMessage() method

C Using onmessage event handler

D Using subscribe() method

The main thread listens for messages from a Web Worker using the onmessage event handler.

Explain how Web Workers improve performance in Angular apps and describe how you would set one up.

Think about separating heavy work from the UI thread.

Describe the communication process between the Angular main thread and a Web Worker.

Focus on message passing methods.