In Angular, the _____ pipe is used to automatically update the view with the latest value emitted by an Observable.
- async
- refresh
- subscribe
- update
In Angular, the async pipe is used to automatically update the view with the latest value emitted by an Observable. It simplifies data binding.
For testing dynamic behavior in directives, such as responding to user input or changes in data, you can use _______.
- Jasmine
- Mocks
- Spies
- TestBed
To test dynamic behavior in directives, you can use Jasmine for its testing capabilities, including spies for tracking function calls.
A cold observable starts emitting values only when it has at least one subscriber.
- delayed
- hot
- multicasting
- synchronous
A cold observable starts emitting values only when it has at least one subscriber.
Which type of Angular directive is responsible for manipulating the structure of the DOM?
- Attribute Directives
- Component Directives
- Pipe Directives
- Structural Directives
Structural directives are responsible for manipulating the structure of the DOM. They change the layout of the view by adding or removing elements from the DOM based on certain conditions or logic.
You are building an Angular application with a complex form. You want to create an E2E test using Protractor to ensure that the form validation works correctly and that the user can submit the form. What steps would you need to include in your test?
- Simulate user interaction
- Submit the form
- Test input validation
- Verify the response from the server
When creating an E2E test for form validation in Protractor, you should test input validation, including various valid and invalid inputs. You also need to simulate user interaction (e.g., entering data), submit the form, and finally verify the response from the server to ensure the form functions correctly.
You're tasked with creating a set of UI components that can be reused in non-Angular projects, such as React or Vue.js applications. Which Angular feature would be most suitable for this task?
- Angular Directives
- Angular Elements
- Angular Modules
- Angular Services
To create UI components that can be reused in non-Angular projects, you can use Angular Elements, which allows you to package Angular components as custom elements that can be used in other frameworks like React or Vue.js.
You are working on an Angular application that uses NgRx for state management. You need to implement a feature where a user action dispatches multiple actions sequentially. How would you achieve this?
- Create a custom service that manually dispatches actions in a sequential manner, and use it in your components.
- Use the mergeMap operator from RxJS to handle the sequential dispatch of actions in an effect.
- Use the pluck operator from RxJS to extract data from the store and dispatch actions sequentially.
- Use the switchMap operator from RxJS to handle the sequential dispatch of actions in an effect.
To achieve sequential dispatch of actions in an NgRx-based Angular application, you can use the mergeMap operator from RxJS within an effect. This operator allows you to handle actions sequentially and maintain the order of dispatch.
A common practice to validate a group of related form controls is to use a custom _____ validator in Angular.
- Reactive Forms
- Reactive Forms
- Template-driven
- Template-driven
In Angular, a common practice to validate a group of related form controls is to use a custom Reactive Forms validator.
How can you dynamically add a new control to a Form Array in Angular?
- formArray.addControl(control)
- formArray.createControl(control)
- formArray.insert(index, control)
- formArray.push(control)
To dynamically add a new control to a Form Array in Angular, you can use the push method, which adds the control to the end of the array.
To manually check a component and its children, you can inject the _____ service and call its detectChanges() method.
- ChangeDetectorRef
- ComponentCheckService
- ManualDetectionService
- OnCheckService
To manually check a component and its children in Angular, you can inject the ChangeDetectorRef service and call its detectChanges() method. This allows you to trigger change detection explicitly, which can be useful in specific scenarios where automatic change detection is not sufficient.