You're building an admin dashboard with multiple sections like Users, Reports, and Settings. Each section has its sub-sections. What's the most efficient way to structure the routes in Angular to ensure code-splitting and modularity?
- Create a single monolithic routing module
- Implement routing guards for each section
- Use a hierarchical route structure with lazy-loaded modules
- Use a single route configuration file for all sections
The most efficient way to structure routes in Angular for an admin dashboard with multiple sections and sub-sections is to use a hierarchical route structure with lazy-loaded modules. This approach promotes code-splitting and modularity, ensuring that each section and its related functionality are loaded only when needed.
How does Angular ensure that a module is only loaded once regardless of how many times it is lazily loaded?
- Angular maintains a global module registry
- Modules are inherently singletons
- Modules are loaded using the HttpClientModule
- Modules must be explicitly marked as singletons
In Angular, modules are inherently singletons. This means that once a module is loaded, it is cached and reused throughout the application. Even if it's lazily loaded in multiple places, the same instance is shared, reducing duplication and improving performance.
Which Angular testing utility is used to create a dynamic testing module?
- AngularTestingModule
- ComponentFixture
- TestBed
- TestBedModule
TestBed is an essential Angular testing utility used to create a dynamic testing module. It allows you to configure and initialize the testing environment for Angular components and services, providing a controlled context for testing.
When generating a new component using Angular CLI, how can you ensure that it does not produce a separate CSS file but instead uses inline styles?
- Modify the "angular.json" file
- Set a global CSS configuration
- Use the "--inlineStyle" flag
- Use the "ng configure component" command
To generate a new component using Angular CLI and ensure that it uses inline styles (no separate CSS file), you can use the "--inlineStyle" flag with the "ng generate component" command. This will generate a component with the styles included directly in the component file.
Which of the following is a core principle of the NgRx library?
- Component-based Architecture
- Observables
- Two-way Data Binding
- Unidirectional Data Flow
A core principle of the NgRx library is "Unidirectional Data Flow." It emphasizes that data flows in one direction through your application, making it easier to understand and reason about how data changes occur. This pattern helps manage state and side effects more predictably.
An application form has a section that should only become available if the user selects a specific option in a dropdown menu. Which Angular feature would you use to conditionally display this section?
- *ngIf directive
- Angular routing
- ngClass directive
- Angular modules
To conditionally display a section in Angular based on user input, you would use the *ngIf directive (Option 1). This directive allows you to evaluate an expression and render or remove elements accordingly. Angular routing (Option 2) is used for navigating between different views, ngClass (Option 3) for applying CSS classes conditionally, and Angular modules (Option 4) are used for organizing and structuring an application.
How can you bind an event to a button click in Angular?
- Using ngSwitch
- Using ngModel
- Using ngClass
- Using (click) syntax
In Angular, you can bind an event to a button click using the (click) syntax. For example, you can use (click)="functionName()" to trigger a function when the button is clicked. This syntax allows you to specify event bindings in your Angular templates. The other options (ngSwitch, ngModel, ngClass) are used for different purposes and do not directly bind events to button clicks.
If a component has a frequently updating data-bound property, using ChangeDetectionStrategy.______ might lead to unwanted behavior.
- CheckAlways
- CheckOnce
- Default
- OnPush
In Angular, Change Detection is the mechanism that automatically updates the view to reflect the model state. When a component uses ChangeDetectionStrategy.OnPush, it means that change detection is triggered only when the input properties of the component change or when an event is fired from the component itself. Using OnPush can lead to unwanted behavior if a data-bound property frequently updates outside of these triggers, as it may not be detected by Angular.
How can you project content from a parent component to a specific location in a child component?
- By using the
directive. - By using the
element with a selector in the child component's template. - By using the @Input decorator in the child component's TypeScript file.
- By using the Angular CLI command ng project-content.
You can project content from a parent component to a specific location in a child component by using the element with a selector in the child component's template. This selector allows you to define where the content should be placed within the child component's template. It's a crucial technique for creating flexible and reusable components in Angular.
When creating a custom value accessor, the method responsible for setting the control's value based on the form model is called ______.
- setControlValue
- setValue
- updateFormModel
- writeValue
In the context of creating a custom value accessor, the method responsible for setting the control's value based on the form model is called writeValue. This method is part of the ControlValueAccessor interface and is crucial for synchronizing the custom form control's value with the form model.
Which technique in Angular allows you to encapsulate styles and templates so that they don't affect other parts of the application?
- Angular Modules.
- Angular Services.
- Angular Components.
- Angular ViewEncapsulation.
Angular's ViewEncapsulation technique allows you to encapsulate styles and templates for a component so that they don't affect other parts of the application. It provides options like Emulated, None, and Shadow DOM, which control how styles are scoped to a component. The other options, such as Angular Modules and Components, serve different purposes in Angular and do not specifically address style and template encapsulation.
What method can be used to manually trigger change detection in Angular?
- detectChanges()
- runChangeDetection()
- triggerChangeDetection()
- performChangeDetection()
The detectChanges() method can be used to manually trigger change detection in Angular. It is a method of the ChangeDetectorRef class and is often used when you need to explicitly check for changes in a component, especially when dealing with components that use the OnPush change detection strategy. The other options (runChangeDetection(), triggerChangeDetection(), performChangeDetection()) are not standard Angular methods.