In template-driven forms, how can you access the overall form status?
- Accessing the formStatus variable
- By calling the this.formStatus() method
- Using the ngForm directive
- Utilizing the form property in a template
In template-driven forms, you can access the overall form status by utilizing the 'form' property in a template. This 'form' property provides information about the form's status, such as whether it's valid, invalid, or pristine. It's a built-in feature for managing and validating forms in Angular.
What's the benefit of using immutable data structures in Angular applications?
- They allow for more efficient data binding.
- They can be easily modified in-place.
- They simplify the component creation process.
- They enhance code readability.
Using immutable data structures in Angular provides benefits like more efficient data binding. Immutable data structures prevent unexpected changes to the data, making it easier to track changes in the application state. They also help optimize change detection, leading to better performance. While the other options may have their merits, they do not directly address the benefits of immutability in Angular.
How would you retrieve query parameters from the current route in an Angular application?
- Using the ActivatedRoute service's queryParams property.
- By accessing the router state's queryParameters property.
- Through the RouterLinkActive directive.
- By subscribing to the router's queryParams observable.
To retrieve query parameters from the current route in an Angular application, you would typically use the ActivatedRoute service's queryParams property. This property provides access to the parsed query parameters, allowing you to read and utilize them within your component. The other options are not the standard way to access query parameters in Angular. The RouterLinkActive directive is used for styling active links, not for parameter retrieval.
For handling offline data synchronization in an Angular app, which RxJS operator would be most appropriate?
- catchError
- mergeMap
- publishReplay
- retry
To handle offline data synchronization in an Angular app, the publishReplay operator can be most appropriate. This operator allows you to cache and replay emitted values, making it useful for scenarios where you want to store and replay network requests or data updates when the device is offline and then sync them when it's online.
Your team wants to maintain consistent code style and practices across Angular projects. Which Angular CLI feature would you use to enforce this?
- TSLint
- ESLint
- StyleLint
- Codelyzer
To maintain consistent code style and practices in Angular projects, you would use ESLint. ESLint is a widely-used linting tool that provides extensive configuration options and can enforce coding standards and best practices for TypeScript and JavaScript code, making it a suitable choice for maintaining consistency.
The lifecycle hook ngAfterViewInit is specifically related to a component's child ________.
- Directive
- Element
- Module
- Template
The lifecycle hook ngAfterViewInit is specifically related to a component's child template. This hook is called after Angular has fully initialized a component's view and any child views it contains. It allows you to interact with the template and its elements once they are ready for manipulation.
Which change detection strategy checks the component only when its input properties change?
- ChangeWhenInputChanges
- CheckOnce
- Default
- OnPush
The change detection strategy that checks the component only when its input properties change is "ChangeWhenInputChanges." This strategy is commonly referred to as "OnPush." When using this strategy, Angular will recheck a component only when its input properties change, improving performance by reducing unnecessary checks on components that haven't received new input data.
What's the primary difference between the switchMap and mergeMap operators?
- switchMap and mergeMap are identical and can be used interchangeably.
- switchMap and mergeMap are used for completely different purposes and cannot be compared.
- switchMap cancels the previous inner observable when a new one arrives, while mergeMap concurrently processes all inner observables.
- switchMap processes all inner observables concurrently, while mergeMap cancels the previous inner observable when a new one arrives.
The primary difference is that switchMap cancels the previous inner observable when a new one arrives. In contrast, mergeMap concurrently processes all inner observables it receives. This behavior makes switchMap useful for scenarios where you want to ensure only the latest inner observable result is considered, while mergeMap retains all results from concurrently executing inner observables.
In which scenarios would you consider using ChangeDetectionStrategy.OnPush?
- When the component depends on parent component data changes.
- When the component has frequent, unrelated changes.
- When the component is rarely used in the application.
- When the component needs to check for changes on every interaction.
You would consider using ChangeDetectionStrategy.OnPush in scenarios where the component's updates depend on changes in its parent component. This strategy is beneficial when you want to optimize performance by reducing unnecessary change detection cycles. It's not typically used when a component needs to check for changes on every interaction or when it's rarely used.
A client wants the ability to deep link to specific parts of your Angular application. What would you ensure to accommodate this requirement?
- Utilizing Angular's RouterModule and configuring the application for hash-based routing.
- Disabling routing in the Angular application to prevent deep linking.
- Implementing a custom JavaScript solution for deep linking.
- Creating static HTML pages for each deep linkable section of the application.
To accommodate the client's requirement of deep linking to specific parts of your Angular application, you should use Angular's RouterModule and configure the application for hash-based routing. This approach allows for deep linking by using URL fragments. The other options are not suitable for achieving deep linking in an Angular application.
When creating custom form controls, the method used to write a new value to the view is ______.
- changeValue()
- patchValue()
- setValue()
- updateValue()
In Angular, when creating custom form controls, the method used to write a new value to the view is setValue(). This method allows you to set the value of a FormControl and update the view accordingly. It's a critical method for working with form controls in Angular.
The ngAfterViewInit and ngAfterViewChecked lifecycle hooks are related to a component's ________.
- OnDestroy
- OnInit
- View Initialization
- View Rendering
These lifecycle hooks, ngAfterViewInit and ngAfterViewChecked, are related to a component's view rendering process in Angular. ngAfterViewInit is called after the view and its child views (if any) have been initialized, and ngAfterViewChecked is called after every check of the component's view and child views. These hooks allow developers to perform actions after the view has been created or updated.