You are building a large e-commerce application and you want to ensure that certain modules, like the Checkout module, are only loaded when the user navigates to that section. How would you achieve this?
- Dynamic import() in JavaScript to load modules asynchronously
- Lazy loading with Angular Routing
- Using Webpack code splitting during the build process
- Using ngModule imports in Angular module configurations to control module loading
In Angular, you can achieve lazy loading of modules, such as the Checkout module, using Angular Routing. It allows you to load modules on-demand when a specific route is accessed, improving performance by reducing initial load times.
You are building a component that fetches data from an API. However, you want to ensure that the component only triggers the API call when it's actually visible to the user. Which lifecycle hook can help you achieve this?
- ngAfterViewInit Lifecycle Hook
- ngDoCheck Lifecycle Hook
- ngOnDestroy Lifecycle Hook
- ngOnInit Lifecycle Hook
To ensure that the component triggers the API call when it's actually visible, you can use the ngAfterViewInit lifecycle hook, which is called after the component's view has been initialized.
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.
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.
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.
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.
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.
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.
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.
In Angular, the method used to add a new form control to a FormArray dynamically is ____.
- addFormControl
- appendControl
- createControl
- pushControl
In Angular, the method used to add a new form control to a FormArray dynamically is appendControl. This method allows you to dynamically add a new form control to an existing FormArray.