After creating a dynamic component, if you want to access its instance and modify some properties, you can obtain it through the ______ property of the reference.
- instance
- componentRef
- componentInstance
- dynamicComponent
After creating a dynamic component in Angular, if you want to access its instance and modify some properties, you can obtain it through the componentInstance property of the reference (e.g., ComponentRef). This allows you to interact with the dynamically created component and make changes as needed. The other options are not the standard properties for accessing the instance.
What purpose does the redirectTo property serve in Angular's routing configuration?
- It navigates to the route specified when the application starts.
- It redirects to a specific route if the current route is empty.
- It sets up a wildcard route for unmatched routes.
- It specifies the route to be used when an error occurs.
The redirectTo property in Angular's routing configuration serves to redirect to a specific route if the current route is empty. This is often used to define default routes or to ensure that users are directed to a particular route when they access the application's root URL. It helps improve user experience by ensuring they are on a meaningful route.
Which Route Guard is especially useful for feature modules that are lazy-loaded?
- CanActivate
- CanDeactivate
- CanLoad
- CanUnload
The CanLoad Route Guard is especially useful for feature modules that are lazy-loaded. It allows you to prevent the lazy-loaded module from being loaded if certain conditions are not met, such as authentication or authorization checks.
In the context of the ControlValueAccessor interface, which method is responsible for registering a callback to be triggered when the control's value changes in the UI?
- registerOnChange
- writeValue
- setViewValue
- registerOnTouched
In the context of the ControlValueAccessor interface, the registerOnChange method is responsible for registering a callback to be triggered when the control's value changes in the UI. This callback allows you to capture and respond to changes in the value of the form control. The other options (writeValue, setViewValue, registerOnTouched) have different purposes within the interface, such as updating values or handling touch events, but do not handle value change notifications.
Imagine you're building a dashboard application where widgets can be added/removed by users. Which feature of Angular would be most suitable to achieve this dynamic behavior?
- Angular Components
- Angular Directives
- Angular Forms
- Angular Services
Angular Components are the most suitable for achieving dynamic behavior where widgets can be added or removed by users in a dashboard application. Components encapsulate the behavior and appearance of UI elements, making them reusable and easy to manage. While directives, services, and forms are essential in Angular, they are not as well-suited to handle the dynamic nature of widgets in this scenario.
For a router link to get an "active" CSS class when the link's route is active, you can use the ________ directive.
- [activeLink]
- [routerDirective]
- [routerLinkActive]
- [routerStyle]
To ensure that a router link receives an "active" CSS class when its associated route is active, you can use the [routerLinkActive] directive in Angular. This directive allows you to define CSS classes that should be applied when the link's route is active, providing visual feedback to users.
A client wants certain fields in a form to be auto-populated based on the value of another field. How would you achieve this in Angular?
- Implementing custom validation for auto-population
- Using pipes to manipulate the form data
- Using reactive forms with value changes observables
- Using template-driven forms with ngModel
To auto-populate fields based on another field's value, you'd typically use reactive forms in Angular along with valueChanges observables. This allows you to reactively update form fields based on changes in other fields. While template-driven forms with ngModel can achieve some level of auto-population, reactive forms provide more control and flexibility. Using pipes or custom validation may not be the most suitable approach for this requirement.
Which decorator is used to declare a class as an Angular component?
- @Component
- @Directive
- @Injectable
- @NgModule
The @Component decorator is used to declare a class as an Angular component. Components are the fundamental building blocks of Angular applications, representing user interface elements. NgModule is used to define modules, @Directive is used for custom directives, and @Injectable is used for dependency injection, but they are not used to declare components.
When dealing with a custom component that doesn't naturally fit into Angular's form ecosystem, which strategy can be employed to ensure it works with ngModel and formControl directives?
- Creating a separate service for form control interactions.
- Implementing a custom directive to handle ngModel and formControl.
- Modifying Angular's core source code to accommodate custom components.
- Using custom event emitters for data binding.
To make a custom component work with ngModel and formControl in Angular, you should implement a custom directive that uses ControlValueAccessor. This allows the component to interface with Angular's form system seamlessly, enabling data binding and validation. Modifying Angular's core source code is not a recommended approach.
What is the primary use of the @Input() decorator in a component?
- To declare a component
- To declare a service
- To declare a variable
- To declare an Angular module
The primary use of the @Input() decorator in a component is to declare a variable as an input property. This allows data to be passed into the component from its parent component. Input properties enable communication between components, making it possible to send data from a parent component to a child component. It is not used to declare services, components, or Angular modules.