You have a component that fetches and displays user data. You want to ensure that if the component is destroyed, the subscription to the Observable fetching the data is also terminated. How would you achieve this?
- Manually unsubscribing in ngOnDestroy()
- Using a takeUntil() operator with ngOnDestroy()
- Using a timeout operator with RxJS complete()
- Using async pipe with RxJS finalize() operator
To ensure the subscription is terminated when the component is destroyed, you can use the takeUntil() operator in combination with ngOnDestroy(). This allows you to unsubscribe when the component's lifecycle ends, preventing memory leaks.
You are implementing a multi-step form where the user can navigate between different sections before submitting the entire form. How would you manage and validate the data of this form using Angular?
- Create a separate FormGroup for each step of the form and validate individually
- Implement server-side validation to handle multi-step form data
- Use a single FormGroup for the entire form and use conditional validation rules
- Utilize Angular services to manage form data across multiple steps
In a multi-step form, it's advisable to create separate FormGroup instances for each step of the form. This allows you to manage and validate the data for each step individually, providing a better user experience.
To transform the items emitted by an Observable and emit the transformation as an Observable, you can use the _____ operator.
- map
- mergeMap
- switchMap
- transform
To transform the items emitted by an Observable and emit the transformation as an Observable, you can use the map operator in RxJS.
Which Angular class is commonly used to programmatically create form controls in a dynamic form?
- DynamicFormBuilder
- FormBuilder
- FormControl
- NgForm
In Angular, the class commonly used to programmatically create form controls in a dynamic form is the FormBuilder. It provides methods for creating form controls and groups programmatically, simplifying the process of working with forms.
What is the purpose of the fixture in Angular testing?
- To create a component
- To define routing
- To set up a testing module
- To simulate user interactions
The fixture in Angular testing is used to simulate user interactions and provides access to the component's DOM for testing.
The Ivy Renderer in Angular optimizes the application by using _____ rendering.
- Asynchronous
- Client-side
- Server-side
- Synchronous
The Ivy Renderer in Angular optimizes the application by using Asynchronous rendering to improve performance.
What is the main benefit of using child routes in Angular applications?
- Creating shared services
- Handling HTTP requests
- Lazy loading components
- Navigating to the parent
The main benefit of using child routes in Angular is lazy loading components, which improves performance by loading components on demand.
You have an Observable stream of user actions in your application. You want to perform a side effect, such as logging, each time an action occurs without modifying the original stream. Which RxJS operator should you use?
- do (or tap)
- filter
- map
- take
When you want to perform side effects on an observable stream without modifying the data, you should use the do (or tap) operator. This allows you to perform actions like logging or debugging without altering the original stream.
When creating a custom pipe, implementing the _____ interface ensures that the pipe recalculates only when the input values change.
- DynamicPipe
- OnChanges
- PipeTransform
- PipeUpdate
When creating a custom pipe in Angular, implementing the PipeTransform interface ensures that the pipe recalculates only when the input values change.
In a reactive form, the _____ method is used to update the value of a form control programmatically.
- patchValue()
- reset()
- setValue()
- updateValueAndValidity()
In a reactive form, the patchValue() method is used to update the value of a form control programmatically. This method allows you to set specific control values.