In Angular, how can you prevent the default form submission behavior of a page reload?
- Set action="javascript:void(0)"
- Use (click)="preventDefault()"
- Use (ngSubmit)="onSubmit($event)"
- Use (submit)="preventDefault()"
To prevent the default form submission behavior of a page reload in Angular, you should use (ngSubmit)="onSubmit($event)" and handle the form submission in your component.
What is the difference between a BehaviorSubject and a ReplaySubject?
- A BehaviorSubject emits all previous values
- A BehaviorSubject emits the last value
- A ReplaySubject emits all previous values
- A ReplaySubject emits the last value
The key difference is that a BehaviorSubject emits only the last value upon subscription, while a ReplaySubject emits all previous values to new subscribers.
What is the purpose of the setValue and patchValue methods in Angular Reactive Forms?
- They both reset the form
- They both set the entire form
- patchValue sets partial values
- setValue sets a specific value
In Angular Reactive Forms, setValue sets the entire form, while patchValue sets partial values. patchValue is commonly used to update specific form controls.
What is the main benefit of using Ivy Renderer in Angular applications?
- Better error handling
- Enhanced routing and navigation
- Faster rendering
- Improved tree-shaking
The main benefit of using the Ivy Renderer in Angular applications is faster rendering, which results in improved application performance.
When testing a pipe, you need to check if the ______ is transformed correctly to the desired output.
- Input HTML
- Input data
- Input expression
- Input function
When testing a pipe, you need to check if the input data is transformed correctly to the desired output based on the pipe's logic.
How can you use a different class or value in place of a service in testing or certain scenarios?
- Dependency injection
- Extending the service class
- Mocking
- Using abstract classes
You can use a different class or value in place of a service in testing or specific scenarios by mocking the service using testing libraries or creating custom mock objects.
What does the ng add command do in Angular CLI?
- Add a new component
- Add a new dependency
- Generate a service using the CLI
- Remove an existing component
The ng add command in Angular CLI is used to add a new dependency to the Angular project, such as a library or package.
What is the purpose of Angular's built-in debugger statement?
- To debug TypeScript code
- To optimize performance
- To provide error messages
- To stop execution
The purpose of Angular's built-in debugger statement is to debug TypeScript code by pausing execution at a specific point in the code for inspection and troubleshooting.
To share a single subscription among multiple subscribers and turn a cold observable into a hot one, you can use the _____.
- Collect
- Connect
- Merge
- Share
To share a single subscription among multiple subscribers and turn a cold observable into a hot one, you can use the Share operator. This allows multiple subscribers to share the same execution of the observable, reducing duplicate work.
You want to track the time taken for a user to navigate from one page to another in your Angular application. Which Router Events can be useful for this purpose?
- NavigationEnd and RoutesRecognized
- NavigationStart and NavigationCancel
- NavigationStart and NavigationEnd
- NavigationStart and NavigationError
To track the time taken for navigation, you can use NavigationStart and NavigationEnd Router Events. The NavigationStart event marks the start of navigation, and NavigationEnd marks the end. Combining them allows you to measure the time taken.
You are building a dashboard and have created a "UserCard" component to display user details. You want this component to display user details differently based on the type of user (Admin, Guest, Registered). Which feature of Angular components can help you achieve this without creating multiple components?
- Component Inheritance
- Content Projection
- Interpolation
- Structural Directives
In this scenario, Structural Directives like *ngIf and *ngSwitch allow you to conditionally render content within a single component, enabling you to display user details differently based on the type of user.
Which RxJS operator is best suited for performing side effects in an Observable chain?
- filter
- map
- reduce
- tap
The tap operator in RxJS is specifically designed for performing side effects (such as logging, making API calls, or modifying data) in an Observable chain.