How can you pass data to a dynamically created component?
- Using Angular's data binding with @Input().
- By directly modifying the component's internal state.
- Through a centralized data store like Redux.
- By using Angular services and injecting data.
To pass data to a dynamically created component in Angular, you can use Angular's data binding with @Input() decorators. This allows you to bind properties of the dynamic component to the parent component's properties, enabling seamless data communication between them. The other options may be possible in certain scenarios but are not the standard approach for passing data to dynamically created components.
Your application requires a custom directive that modifies the structure of the DOM based on user roles. Which type of directive should you consider creating?
- Attribute Directive
- Component Directive
- Service Directive
- Structural Directive
When you need to modify the structure of the DOM based on user roles, a Structural Directive is the most appropriate choice. Structural Directives, such as ngIf and ngFor, can conditionally add or remove elements from the DOM, allowing you to customize the view based on user roles or conditions. This flexibility makes them well-suited for this scenario.
An Observable that can emit multiple values over time is different from a Promise, which can resolve only ________.
- multiple times
- never
- once
- twice
An Observable can emit multiple values over time, whereas a Promise can resolve only once. This fundamental difference makes Observables suitable for handling asynchronous streams of data, while Promises are used for handling single asynchronous operations.
Which decorator is used to inject a service into an Angular component?
- @Injectable()
- @Component()
- @Service()
- @InjectService()
To inject a service into an Angular component, you use the @Injectable() decorator. This decorator is applied to the service class, allowing Angular's dependency injection system to recognize and provide the service when requested by a component. The other options (@Component(), @Service(), @InjectService()) are not used for this purpose.
When using the OnPush strategy, a component will be checked if a new object reference is passed to one of its ________.
- Inputs
- Methods
- Outputs
- Variables
When using the OnPush change detection strategy in Angular, a component will be checked if a new object reference is passed to one of its inputs. This means that the component will only re-render if there's a change in the input values. The OnPush strategy is an optimization to reduce unnecessary checks and re-renders.
Change detection in Angular can be optimized by ensuring data structures are ________.
- Encapsulated
- Immutable
- Mutable
- Private
Change detection in Angular can be optimized by ensuring data structures are immutable. Immutable data structures ensure that when changes are made to data, a new reference is created, which helps Angular's change detection mechanism identify changes efficiently. By contrast, mutable data structures may not trigger change detection as expected.
What is the main advantage of using Lazy Loading in Angular applications?
- Enhanced SEO
- Faster initial loading
- Improved rendering performance
- Smaller bundle sizes
The main advantage of using Lazy Loading in Angular applications is faster initial loading. Lazy loading allows you to load specific parts of your application only when they are needed, reducing the initial bundle size and improving the loading speed.
In an e-commerce application, you want to ensure that cart-related operations are handled by a single instance of a service, but product listing operations can have different service configurations on different pages. How would you structure your services?
- Create a separate service for each product listing page, each with its unique configuration.
- Create a shared service for cart-related operations and use Angular's providedIn to provide it at the root level.
- Create a single service with conditional logic to handle both cart and product listing operations.
- Use Angular's built-in services for cart operations and create custom services for product listing operations.
To ensure that cart-related operations are handled by a single instance of a service, you can create a shared service for cart operations and provide it at the root level using Angular's providedIn. For product listing operations with different configurations on different pages, separate services for each page may be necessary to manage unique settings.
The method setValidators() and clearValidators() belong to the ______ class in Angular's Reactive Forms.
- AbstractControl
- FormControl
- FormGroup
- FormValidator
The methods setValidators() and clearValidators() belong to the AbstractControl class in Angular's Reactive Forms. AbstractControl is a common base class for FormControl, FormGroup, and FormArray. These methods allow developers to set and clear validation functions for form controls, providing control over input validation in reactive forms.
Angular provides a set of classes like Renderer2 and ______ to safely manipulate the DOM without direct access.
- DomHelper
- DomManipulator
- ElementRef
- Renderer3
Angular provides a set of classes like Renderer2 to safely manipulate the DOM without direct access. These classes abstract away direct DOM manipulation, promoting a safer and more Angular-friendly way to interact with the DOM. ElementRef is used to access the underlying DOM element, not to manipulate it directly. DomManipulator and Renderer3 are not standard Angular classes.