What's the purpose of the FormBuilder service in Angular's reactive forms?

  • It's used for styling forms with CSS.
  • It's used to create form controls manually.
  • It's used to handle HTTP requests in forms.
  • It's used to simplify the creation of form controls.
The FormBuilder service in Angular's reactive forms is used to simplify the creation of form controls and form groups. It provides a more concise and readable way to define form structures compared to manually creating controls. While Angular also uses HTTP for handling HTTP requests in forms, this is not the primary purpose of FormBuilder. It's primarily focused on form control management.

Which Angular CLI command is used to generate a new service?

  • ng create service
  • ng generate service
  • ng make service
  • ng new service
To generate a new service in an Angular application, you should use the ng generate service command. This command creates the service file, sets up the necessary imports, and registers the service with the Angular dependency injection system.

The ______ directive provides two-way data binding in template-driven forms, synchronizing the form control's value with a property in the component.

  • [(ngModel)]
  • [formModel]
  • [ngBind]
  • [twoWayBinding]
The [(ngModel)] directive provides two-way data binding in template-driven forms. It allows you to bind a form control's value to a property in the component, ensuring that changes to either the form control or the component property are reflected in both directions. This synchronization is a key feature of Angular template-driven forms, making it easy to work with form data in the component.

A component in your application processes and displays data from a third-party service. The data updates very infrequently. To optimize change detection for this component, what would you recommend?

  • Default Change Detection
  • OnPush Change Detection
  • CheckAlways Change Detection
  • Detached Change Detection
In this scenario, when dealing with infrequently updated data from a third-party service, using the OnPush change detection strategy is recommended. OnPush reduces unnecessary re-renders by only updating the component when its input properties change or when explicitly triggered. Default change detection (Option 1) may cause unnecessary updates on every digest cycle, leading to performance issues. CheckAlways (Option 3) and Detached (Option 4) are not typically used for such scenarios.

In large applications, frequent change detection cycles can lead to performance issues, especially if the application does not use the ________ change detection strategy.

  • CheckOnce
  • Default
  • OnPush
  • Push
In large Angular applications, frequent change detection cycles can indeed lead to performance issues. By default, Angular uses the Default change detection strategy, which checks all components in each cycle. To address this, developers can use the ChangeDetectionStrategy.OnPush strategy, which limits change detection to components that receive input changes or manually trigger detection, significantly improving performance for large applications.

A backend API endpoint occasionally fails, and you want to implement a strategy to retry the request three times before giving up. How would you achieve this in Angular?

  • Implement a custom retry mechanism in a service
  • Set the maxRetries configuration option in Angular HTTP Client
  • Use a timeout for three retries in the catch block
  • Use the RxJS retry operator with a count of 3
To implement a strategy to retry an HTTP request three times before giving up in Angular, you should use the RxJS retry operator with a count of 3. This operator allows you to specify the number of retry attempts for a failed request, helping you achieve the desired retry behavior.

To define specific styles that apply only to a component and do not affect any external elements, you'd set the component's encapsulation property to ViewEncapsulation.______.

  • None
  • ShadowDom
  • Emulated
  • Native
In Angular, the encapsulation property determines how styles are scoped for a component. Setting it to Emulated (or None for no encapsulation) ensures that styles apply only to the component and its descendants, not affecting external elements. This is often used to create encapsulated styles for Angular components. The other options (ShadowDom and Native) represent different encapsulation methods, but Emulated is the correct option for this scenario.

Which command or flag should you use with Angular CLI if you want to analyze the size of your bundles?

  • "ng analyze"
  • "ng build --stats-json"
  • "ng bundle-analysis"
  • "ng size-check"
To analyze the size of your bundles in an Angular application, you should use the "ng analyze" command. This command provides detailed information about the size of your application's bundles, including dependencies and modules.

A service provided at the component level will create a new instance for each ________ of the component.

  • 'child component'
  • 'function'
  • 'instance'
  • 'module'
A service provided at the component level will create a new instance for each 'instance' of the component. This means that every time a new instance of the component is created, a new instance of the service will also be created, ensuring that each component instance has its own isolated instance of the service.

Which operator is best suited for handling multiple click events in rapid succession with RxJS in Angular?

  • debounceTime()
  • filter()
  • map()
  • switchMap()
The debounceTime() operator in RxJS is best suited for handling multiple click events in rapid succession. It allows you to specify a time window during which it will ignore subsequent events, which is ideal for scenarios where you want to debounce click events to avoid processing them too quickly. The other operators have different use cases and are not specifically designed for this scenario.