What is a directive in Angular?
- A behavior added to DOM
- A component template
- A module definition
- A route configuration
In Angular, a directive is a behavior added to the Document Object Model (DOM) to extend its functionality. Directives are a way to create reusable components and add dynamic behavior to elements.
In the context of Angular Elements, what is the purpose of the createCustomElement() function?
- To create Angular modules
- To create custom HTML elements
- To define custom CSS styles
- To enable Angular routing for elements
In the context of Angular Elements, the createCustomElement() function is used to create custom HTML elements. It takes an Angular component and returns a custom element (Web Component) that can be used in non-Angular environments. This function allows Angular components to be utilized as custom elements with their own HTML tags.
You've noticed that a specific component in your application is being checked and re-rendered by Angular even though its input data hasn't changed. You want to optimize it so that Angular only re-renders it when the input data actually changes. What would you implement?
- Change Detection Strategy
- Dependency Injection
- Pure Pipe
- ngOnChanges Lifecycle Hook
To optimize re-rendering, you should implement a Change Detection Strategy, such as OnPush, to make Angular re-render the component only when its input data changes.
Which file in an Angular component contains metadata and helps Angular understand how to process a class?
- app.component.ts
- app.module.ts
- index.html
- styles.css
In Angular, the file that contains metadata and helps Angular understand how to process a class is app.component.ts.
How can you share a single Observable execution between multiple subscribers?
- Using the filter() operator
- Using the map() operator
- Using the mergeMap() operator
- Using the share() operator
You can share a single Observable execution between multiple subscribers by using the share() operator. This allows multiple subscribers to share the same execution and results of the Observable.
What is the primary purpose of End-to-End (E2E) testing in an Angular application?
- Test Angular services
- Test individual components
- Test server-side logic
- Test the user interface
The primary purpose of E2E testing in an Angular application is to test the user interface to ensure that all parts of the application work together as expected.
How does the Ivy Renderer's instruction set contribute to improved performance in Angular applications?
- Enables Ahead-of-Time (AOT) compilation
- Minimizes network requests
- Optimizes the rendering process
- Reduces JavaScript bundle size
The Ivy Renderer's instruction set in Angular contributes to improved performance by optimizing the rendering process, resulting in faster component rendering.
What would you use to ensure that a route is only accessible to authenticated users?
- CanActivate guard
- Route event emitter
- Route resolver
- Router outlet
To ensure that a route is only accessible to authenticated users, you would use a CanActivate guard. CanActivate guards can be used to implement authentication and authorization checks before allowing access to a route.
What is the main advantage of using a Subject over a standard Observable?
- Subjects allow multicasting
- Subjects are faster in emitting values
- Subjects are more memory-efficient
- Subjects provide better error handling
The primary advantage of using a Subject over a standard Observable is that Subjects allow multicasting, making it possible to share values with multiple subscribers.
What is the purpose of using the resolve property in Angular routing?
- Define route aliases
- Load data before activating
- Preload lazy-loaded modules
- Redirect to a default route
The purpose of using the resolve property in Angular routing is to load data before activating a route, ensuring that data is available for the component.
What is the primary purpose of unit testing Angular components?
- Ensure compatibility
- Test the end-to-end flow
- Validate REST APIs
- Verify component templates
The primary purpose of unit testing Angular components is to verify component templates, ensuring they render as expected and contain the desired logic.
What is the primary purpose of using custom pipes in Angular applications?
- Create modules and services
- Handle routing and navigation
- Modify the component's class properties
- Transform and format data
The primary purpose of using custom pipes in Angular is to transform and format data before displaying it in the view. Custom pipes allow you to apply specific transformations to data.