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.
You're building a tab component system where each tab can have custom content. Which Angular feature would be most appropriate to allow users to define content for each tab?
- Content Projection (ng-content)
- Dependency Injection (DI)
- Input Properties (Bindings)
- Output Properties (Events)
In Angular, Content Projection (ng-content) is the most appropriate feature to allow users to define custom content for each tab. It allows users to pass in content that will be inserted into designated placeholders within your component. Input properties allow data binding, output properties handle events, and Dependency Injection is used for providing services, making Content Projection the correct choice for this scenario.
For a CanDeactivate guard, which method parameter allows you to access the current instance of the component being deactivated?
- component
- componentInstance
- currentComponent
- instance
In a CanDeactivate guard, the componentInstance parameter allows you to access the current instance of the component being deactivated. You can use this parameter to interact with the component and make decisions based on its state.
What's a key difference between Just-in-Time (JIT) and Ahead-of-Time (AOT) Compilation in Angular?
- AOT compiles at runtime
- AOT produces readable TypeScript code
- JIT compiles at runtime
- JIT produces smaller bundle sizes
JIT (Just-in-Time) compilation in Angular compiles the application's TypeScript code into JavaScript at runtime, whereas AOT (Ahead-of-Time) compilation compiles the code during the build process, producing optimized and smaller JavaScript bundles, which results in faster loading times and better performance.
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.