How can you run a subset of your E2E tests using Protractor?
- Use the --grep flag
- Use the --only flag
- Use the --suite flag
- Use the --tags flag
To run a subset of E2E tests in Protractor, you can use the --grep flag to specify a regular expression to match test names.
What Angular service allows you to access the route parameters in the component class?
- ActivatedRoute
- HttpClient
- Router
- RouterModule
The Angular service that allows you to access the route parameters in the component class is ActivatedRoute. You can use it to access information about the activated route, including its parameters.
You have a large suite of Jasmine tests. Some of them take a long time to execute and are causing your development workflow to slow down. What can you do to speed up the test execution process without compromising code quality?
- Increase test complexity
- Optimize test environment setup
- Parallelize test execution
- Reduce test coverage
To speed up test execution without compromising code quality, you can parallelize test execution to run multiple tests simultaneously, improving efficiency.
To use a custom pipe in a template, you have to add it to the _____ array in the module.
- bootstrap
- declarations
- imports
- providers
To use a custom pipe in a template, you have to add it to the declarations array in the module.
How can you optimize the performance of two-way data binding for large forms in Angular?
- Implement a custom change detection logic
- Increase the change detection frequency
- Use reactive forms
- Use template-driven forms
To optimize the performance of two-way data binding in large forms, you should use reactive forms in Angular.
You are building a real-time dashboard that fetches data from multiple sources. You want to update the UI as soon as any of the data sources emit a new value. Which RxJS operator would be most suitable for this use case?
- concatMap
- exhaustMap
- mergeMap
- switchMap
In this scenario, you should use switchMap, which switches to the latest observable whenever a new one arrives, effectively updating the UI as soon as any source emits new data.
Imagine you're building an Angular application that requires a directive to format and validate phone numbers in real-time. How would you implement this functionality?
- Create a component to handle phone number formatting and validation
- Create a service for formatting and validation
- Implement a custom directive to handle formatting and validation
- Use Angular's built-in ngModel and ngModelChange to format and validate phone numbers
To achieve this functionality, you would implement a custom directive to format and validate phone numbers. Directives are used to add behavior to DOM elements.
When combining multiple Observables but wanting to trigger an emission only when any one of them emits a new value, the _____ operator can be used.
- concatMap
- forkJoin
- merge
- switchMap
When combining multiple Observables and triggering an emission upon any of them emitting a value, you can use the forkJoin operator.
You are implementing a long-polling mechanism in an Angular service and notice that the service continues to poll even after navigating away from the component that initiated the polling. How can you prevent this unnecessary network activity?
- Implement a timer-based mechanism
- Terminate the service manually
- Use an if statement to check the component's status
- Use takeUntil with a component's lifecycle event
To prevent unnecessary network activity, you can use takeUntil with a component's lifecycle event, which will automatically unsubscribe when the component is destroyed.
What is the purpose of testing a custom directive in Angular?
- To ensure proper routing
- To validate directive behavior
- To validate service calls
- To verify component data
Testing a custom Angular directive is essential to validate directive behavior and ensure that it functions as expected when applied to elements.