Imagine you're building an Angular application that requires a directive to format and validate phone numbers in real-time. How would you implement this functionality?
- Create a component to handle phone number formatting and validation
- Create a service for formatting and validation
- Implement a custom directive to handle formatting and validation
- Use Angular's built-in ngModel and ngModelChange to format and validate phone numbers
To achieve this functionality, you would implement a custom directive to format and validate phone numbers. Directives are used to add behavior to DOM elements.
You are building a real-time dashboard that fetches data from multiple sources. You want to update the UI as soon as any of the data sources emit a new value. Which RxJS operator would be most suitable for this use case?
- concatMap
- exhaustMap
- mergeMap
- switchMap
In this scenario, you should use switchMap, which switches to the latest observable whenever a new one arrives, effectively updating the UI as soon as any source emits new data.
Angular's change detection mechanism ensures that the _____ is in sync with the component's state.
- DOM
- model
- template
- view
Angular's change detection mechanism ensures that the DOM is in sync with the component's state, ensuring that the view is up-to-date.
How can you handle errors within a Route Resolver?
- Handle errors outside the resolver
- Log the error to the console
- Redirect to an error page
- Rethrow the error to the component
To handle errors within a Route Resolver, you can rethrow the error to the component using an observable with catchError.
What can a Route Resolver return to indicate that the route data is not available?
- Empty object
- Null
- Observable with an error
- Undefined
A Route Resolver can return an Observable with an error to indicate that the route data is not available or there was an issue fetching it.
When you want an Observable to emit a sequence of values over time, you would use _____.
- interval()
- map()
- of()
- timer()
When you want an Observable to emit a sequence of values over time, you would use interval(). The interval() operator emits values at specified time intervals.
In a Protractor test, how can you interact with a button element on a webpage?
- browser.findElement(By.button())
- button.click()
- element(by.button())
- element(by.id())
To interact with a button element in Protractor, you typically use the button.click() method to simulate a click on the button.
To define custom validators in reactive forms, you need to implement a function that returns a/an _____ .
- Array
- Object
- Observable
- ValidatorFn
In reactive forms, custom validators are implemented as functions that return a ValidatorFn, which is used to validate form controls.
To handle browser-specific tasks in an Angular Universal application, you should check if the code is running on the server or the browser using the _____ function.
- checkPlatform
- detectPlatform
- isPlatformBrowser
- isServerSide
In Angular Universal, you should check if the code is running on the server or the browser using the isPlatformBrowser function.
When using a Route Resolver, what impact does it have on the navigation process?
- Cancels navigation if data is missing
- Delays navigation until data is ready
- Improves navigation performance
- No impact
Using a Route Resolver delays navigation until data is ready, ensuring that the component receives the resolved data.
The process of synchronizing the model and the view in both directions is known as _____ data binding.
- Bi-directional
- One-way
- Two-directional
- Two-way
The process of synchronizing the model and the view in both directions is known as Two-way data binding in Angular.
In Angular, when you want to make sure that a service gets instantiated lazily, only when it is needed, you should use _____.
- Eager instantiation
- Lazy loading
- On-demand service
- Singleton
In Angular, to ensure that a service gets instantiated lazily, only when needed, you should use Lazy loading.