What is the purpose of an HttpInterceptor in Angular?
- Intercept and modify HTTP requests and responses
- Manage application state
- Render UI components
- Validate form input
An HttpInterceptor in Angular is used to intercept and modify HTTP requests and responses before they are sent to or received from the server. This allows you to add headers, handle errors, perform logging, or make any necessary changes to the request or response pipeline globally across your application. It is a powerful tool for managing HTTP-related behaviors in a centralized manner.
In a real-time chat application, you need to ensure that even if messages are sent rapidly, only the latest message is processed and displayed. Which RxJS strategy would be most appropriate?
- concatMap
- debounceTime
- exhaustMap
- switchMap
To ensure that only the latest message is processed and displayed in a real-time chat application, you should use the exhaustMap strategy in RxJS. It ensures that only the events from the latest inner observable are propagated.
Which of the following is NOT a valid RxJS operator commonly used in Angular?
- zip
- map
- loop
- switchMap
Among the options provided, "loop" is not a valid RxJS operator. RxJS operators like zip, map, and switchMap are commonly used in Angular for various asynchronous operations such as combining observables, transforming data, and managing concurrent requests.
You are building a multi-step form in your Angular application. Each step should have its own URL path without reloading the entire page. How would you design the routing for this?
- Implement child routes for each step of the form within a parent route. Each child route represents a step, and navigation between steps can be achieved by changing the route.
- Create a single route for the entire form and use JavaScript to load and display different steps dynamically without changing the URL.
- Create a separate component for each form step and use Angular's built-in ngIf directive to conditionally display the steps without changing the URL.
- Use query parameters in the URL to represent the current step, and update the form content based on the parameter value.
To design routing for a multi-step form in Angular with each step having its own URL path, you should implement child routes for each step within a parent route. This allows you to define routes for each form step and navigate between them without reloading the entire page. The other options are either less efficient or do not follow best practices for handling multi-step forms with routing in Angular.
To implement a custom validation directive in template-driven forms, your directive must implement the ______ interface.
- FormControlValidator
- NgFormValidator
- ValidationDirective
- ValidatorDirective
To implement a custom validation directive in template-driven forms, your directive must implement the ValidatorDirective interface. This interface allows you to define custom validation logic for form controls in Angular template-driven forms. It's important to correctly implement this interface to ensure your custom directive can be used effectively for form validation.
In Angular, the _____ decorator is used to bind a property in the child component to receive a value from the parent component.
- @ContentChild
- @Input
- @Output
- @ViewChild
In Angular, the @Input decorator is used to bind a property in the child component, allowing it to receive a value from the parent component. This is commonly used for passing data from a parent to a child component.
When using multi-slot content projection, the content that doesn't match any selector will be projected into the without a select ________.
- Default
- Placeholder
- Slot
- Tag
In Angular, when you use multi-slot content projection, any content that doesn't match any selector will be projected into the element without a select attribute. This is often referred to as the "default" slot, and it's where unmatched content is placed. Options 2, 3, and 4 are not the standard terms used for this behavior.
In NgRx, what is responsible for specifying how state changes in response to actions?
- Actions
- Effects
- Reducers
- Selectors
In NgRx, reducers are responsible for specifying how the state changes in response to actions. Reducers are pure functions that take the current state and an action as arguments and return a new state. They define how the application's state should be updated based on dispatched actions.
Structural directives manipulate the ________ by adding, removing, or replacing elements.
- Angular component structure
- CSS stylesheet structure
- DOM structure
- HTML attributes structure
Structural directives in Angular manipulate the DOM structure by adding, removing, or replacing elements within the DOM. They are a core feature of Angular's template syntax and are used to conditionally render or modify parts of the DOM based on application logic. Understanding how structural directives work is essential for creating dynamic and responsive Angular applications.
What is the primary difference between single-slot and multi-slot content projection?
- Single-slot projects content into a single container, while multi-slot can project content into multiple containers.
- Single-slot requires custom structural directives, while multi-slot uses built-in Angular directives.
- Single-slot is used for simple components, while multi-slot is for complex components.
- Single-slot allows for one-way data binding, while multi-slot enables two-way data binding.
The primary difference between single-slot and multi-slot content projection in Angular is that single-slot projects content into a single container within the component's template, while multi-slot can project content into multiple predefined containers. This allows for more fine-grained control over where different parts of content are placed within the component. The other options do not accurately describe the difference between these two projection methods.