You're building a tabbed interface where only one tab content is displayed at a time, and others are conditionally hidden. Which built-in directive would be most useful to achieve this?
- ngFor Directive
- ngIf Directive
- ngShow Directive
- ngSwitch Directive
To create a tabbed interface where only one tab content is displayed at a time and others are conditionally hidden, the ngIf directive would be most useful. ngIf is a structural directive that conditionally adds or removes elements from the DOM based on a condition. You can use it to conditionally render the content of the selected tab while hiding others.
When you want to get only the first emitted value from an Observable and then complete, you should use the ________ operator.
- debounceTime
- mergeMap
- skip
- take
The take operator in RxJS is used to receive only the first 'n' values emitted by an Observable and then automatically complete the Observable. It's useful when you're interested in a limited initial set of data.
In template-driven forms, which directive is utilized to implement a group of form controls?
- ngControlGroup
- formControlGroup
- ngFormGroup
- formGroup
In template-driven forms, the formGroup directive is used to implement a group of form controls. It allows you to group related form controls together, making it easier to manage their validation and state. The other options mentioned are not valid directives for implementing form control groups in template-driven forms.
Which Angular feature allows you to project different parts of content into multiple predefined slots inside a child component?
- ng-content
- ng-projection
- ng-slot
- ng-template
In Angular, the feature that allows you to project different parts of content into multiple predefined slots inside a child component is the directive. It enables you to define multiple tags with select attributes in the child component's template, and then, in the parent component, specify which content goes into each slot using the select attribute's value. The other options are not valid Angular directives or features for content projection.
If you want to serve your Angular application on a specific port other than the default (4200), which command should you use?
- ng run --port 8080
- ng serve --default-port 8080
- ng serve --port 8080
- ng start --port 8080
To serve your Angular application on a specific port other than the default (4200), you should use the ng serve --port 8080 command. This command starts the development server on port 8080, allowing you to access your application using a different port.
How can you achieve nested routing (child routes) within an Angular application?
- By defining child routes in the RouterModule
- By using Angular's loadChildren feature
- By using Angular's canActivateChild guard
- By applying a deep route nesting hierarchy
To achieve nested routing (child routes) in Angular, you define child routes within the RouterModule configuration. This allows you to create a hierarchical structure of routes. The other options relate to Angular's routing features but do not specifically address the process of achieving nested routes.
What is a potential drawback of not using lazy loading in larger applications?
- Increased memory usage
- Larger initial bundle size
- Reduced component reusability
- Slower application startup
Not using lazy loading in larger applications can result in a larger initial bundle size. This means that users need to download a bigger JavaScript file when they first access the application, which can lead to slower loading times, especially on slower network connections.
Which option is NOT a valid view encapsulation mode in Angular?
- Emulated
- Shadow DOM
- None
- Native
In Angular, the valid view encapsulation modes are Emulated (default), Shadow DOM, and Native. The "None" option is not a valid view encapsulation mode. View encapsulation modes determine how Angular styles are applied and scoped in a component. "None" is not a recognized mode for Angular view encapsulation.
In the context of state management in Angular, what is the role of "selectors"?
- Selectors are responsible for dispatching actions
- Selectors are used to derive data from the store
- Selectors handle side effects
- Selectors provide routing functionality
In Angular state management, "selectors" play a crucial role in deriving and transforming data from the store. They allow you to compute and return specific slices of the application state, making it easier to access and display relevant data in components.
You have a service that makes an HTTP request. You want to test this service without actually hitting the endpoint. How would you achieve this in Angular testing?
- Mock the HTTP service using HttpClientTestingModule
- Use a real HTTP request for accurate testing
- Use a testing library like ng-mocks to mock the HTTP service
- Utilize ng-test-bed to simulate HTTP requests
In Angular testing, you can use a testing library like ng-mocks to mock the HTTP service, allowing you to isolate and control the behavior of the service without making actual network requests. This is essential for unit testing to avoid external dependencies.