Angular Essentials: Signals, Web Workers, and Pre-rendering Quiz Quiz

Test your foundational understanding of Angular's Signals, Web Workers, and Pre-rendering with these easy, concept-driven questions. Sharpen your knowledge for interviews and strengthen your skills in state management, performance optimization, and SEO for Angular apps.

1. Understanding Angular Signals

   In Angular, what is the primary purpose of using a Signal compared to traditional variables or RxJS Observables for state management?

   1. Signals are only used for communicating between two unrelated components.
   2. Signals replace all template logic with CSS.
   3. Signals enable automatic reactivity to state changes with less boilerplate code.
   4. Signals automatically generate HTML templates.

2. Signal Definition Example

   Which of the following code snippets best illustrates how to define and update a Signal for tracking a counter value in Angular?

   1. let count = 0; count++;
   2. const count = signal(0); count.set(count() + 1);
   3. count.signal = 0; update(count.signal + 1);
   4. const count = new Observable(0); count.next(count.value + 1);

3. Difference Between Signals and Effects

   What is the main difference between a Signal and an Effect in Angular?

   1. A Signal holds reactive state, while an Effect reacts to changes in one or more Signals.
   2. An Effect stores values, while a Signal executes functions when events occur.
   3. Effects can only be used in services, but Signals are only for components.
   4. Signals are asynchronous, whereas Effects are synchronous.

4. Signal Tracking in Angular

   How does Angular determine when a component or an Effect must re-execute due to changes in a Signal?

   1. Only through manual calls to a refresh function.
   2. By using event listeners in the template.
   3. Angular randomly checks all values each time.
   4. By tracking which Signals are accessed during execution and re-running when those Signals change.

5. Performance with Signals vs Zone-based Detection

   How do Signals improve performance over zone-based change detection in Angular?

   1. Signals disable all reactivity in templates.
   2. Signals use the DOM directly for updates.
   3. Signals target updates to only components depending on changed Signals, instead of triggering global change detection.
   4. Signals require more resources, slowing down the application.

6. Web Worker Basics

   What does a Web Worker allow you to do in a web application such as Angular?

   1. Replace Angular services with background processes.
   2. Directly manipulate the DOM from multiple threads.
   3. Send emails from the client-side code.
   4. Run computationally intensive JavaScript tasks in a separate background thread.

7. Communicating with Web Workers

   What is the standard method for passing data between the main thread and a Web Worker in Angular?

   1. Modifying global variables accessible to both.
   2. Using postMessage and onmessage events to send and receive data.
   3. Direct function calls between the main thread and worker.
   4. Using HTML forms for communication.

8. Web Worker Limitations

   Which of these statements about Web Workers is correct?

   1. Web Workers are able to store data in the server's filesystem.
   2. Web Workers cannot access the DOM; DOM operations must be handled in the main thread.
   3. Web Workers can directly access and change the HTML page's DOM.
   4. Web Workers run synchronously with the main thread.

9. Understanding Pre-rendering

   What is the main goal of using pre-rendering in an Angular Single-Page Application (SPA)?

   1. Reduce CSS file size automatically.
   2. Disable dynamic routing in the application.
   3. Replace all JavaScript files with HTML files for better performance.
   4. Generate static HTML pages ahead of time for improved SEO and faster initial page loads.

10. Angular Universal Pre-rendering Process

    Which step is essential when setting up pre-rendering with Angular Universal?

    1. Automatically converting all TypeScript files to HTML.
    2. Configuring the Angular app for server-side rendering and specifying routes to be pre-generated.
    3. Using browser-specific APIs during the rendering process exclusively.
    4. Adding pre-rendering by updating only the CSS files.