For a directive to modify the value of a host property, you would use the ______ decorator.
- ElementRef
- HostBinding
- Input
- Output
For a directive to modify the value of a host property, you would use the HostBinding decorator. HostBinding allows you to bind the value of a directive property to a host element's property, effectively modifying the host element's behavior or appearance. This is useful for creating dynamic and interactive custom directives in Angular.
What does the term "Hierarchical Injector" refer to in Angular?
- A design pattern used to structure Angular components hierarchically.
- A type of dependency injection system in Angular that supports multiple hierarchies.
- An Angular feature that allows for dynamic component hierarchies.
- An Angular feature that automatically sorts components in a hierarchical order.
The term "Hierarchical Injector" in Angular refers to a type of dependency injection system that supports multiple hierarchies. In Angular, services can be provided at various levels of the application, and the hierarchical injector helps manage the scope and accessibility of these services. This is crucial for controlling how services are shared and instantiated within different parts of an Angular application.
What is the main purpose of Angular's ChangeDetectionStrategy.OnPush?
- To enable two-way data binding.
- To improve change detection performance.
- To disable change detection altogether.
- To increase the framework's size.
The main purpose of Angular's ChangeDetectionStrategy.OnPush is to improve change detection performance. When you use this strategy, Angular will only perform change detection when input properties of a component change or when certain events are triggered, leading to better performance in applications with complex component trees. The other options are not the main purpose of this strategy.
Why would you use the ViewContainerRef in Angular?
- To manage the DOM elements where dynamic components are inserted.
- To create Angular services.
- To handle form submissions in Angular.
- To define Angular component templates.
ViewContainerRef in Angular is used to manage the DOM elements where dynamic components are inserted. It provides a reference to the container where you can dynamically add or remove components. This is useful for scenarios where you need to render components based on user interactions or application logic. The other options are not the primary purpose of ViewContainerRef.
If you have an application where some modules are loaded on-demand, and you want to restrict this based on user roles, which Route Guard should you implement?
- CanActivate
- CanActivateChild
- CanDeactivate
- CanLoad
To restrict loading of modules based on user roles in a lazy-loaded scenario, you should implement the CanLoad guard. It allows you to check conditions before the module is loaded, ensuring that only authorized users can access certain parts of the application.
What method of HttpClient would you use to send a GET request?
- delete()
- get()
- post()
- put()
To send a GET request using HttpClient, you would use the get() method. This method is used to perform HTTP GET requests to retrieve data from a specified URL.
In Angular's dependency injection, what is the difference between a service provided in 'root' and one provided in a module?
- Services provided in 'root' are lazy-loaded, while those in a module are eager-loaded
- Services provided in 'root' are singletons, while those provided in a module are scoped to that module
- Services provided in 'root' cannot have dependencies, while those in a module can
- Services provided in 'root' have wider accessibility, while those in a module are private
When a service is provided in the 'root' of an Angular application, it becomes a singleton. This means there's only one instance of the service for the entire application. Services provided in a module are scoped to that module, creating a new instance for each module that imports it.
In an e-commerce application, you want to implement a feature to undo the last action (like adding an item to the cart). Which feature of NgRx would you leverage for this?
- Actions
- Effects
- Selectors
- Time-travel debugging
To implement an undo feature in NgRx, you would leverage "Time-travel debugging." This feature allows you to step backward and forward through the state changes, effectively enabling undo and redo functionality in your application.
The routerLink directive can be bound to an array, allowing you to pass ________ to the route.
- arrays
- data
- parameters
- queries
The routerLink directive can be bound to an array, allowing you to pass parameters to the route. This is useful for passing dynamic data to routes, such as route IDs or other contextual information. While the routerLink can also be bound to other types of data, like arrays or queries, it's primarily used for passing parameters.
If two modules provide the same service and are imported into a third module, the service from the ________ module will be used.
- 'first'
- 'second'
- 'third'
- 'third-party'
When two modules provide the same service and are imported into a third module in Angular, the service from the 'first' module will be used. Angular's dependency injection system follows a hierarchical order for providing services. The first module providing the service takes precedence over the second module, and so on. This ensures that the service is consistent and predictable in its usage.