Angular Interview Practice

What is the purpose of the ngClass directive?

1. To handle form input validation

2. To add behavior to components

3. To conditionally apply CSS classes to elements

4. To create responsive layouts

The correct answer is: To conditionally apply CSS classes to elements

The ngClass directive is specifically designed to conditionally apply one or more CSS classes to an HTML element based on the evaluation of an expression. This allows dynamic styling of elements depending on the state of the component. For example, you might want to add a class for active states or change styles based on user interactions or data values. This capability enhances the visual presentation of components and allows developers to create more responsive and user-friendly interfaces. In contrast, handling form input validation is typically managed by the Angular forms module, which focuses on tracking form states and validating user input. Adding behavior to components generally involves using directives or services, which manage the interaction and logic of components beyond visual presentation. Creating responsive layouts usually pertains to the application of CSS or utilizing layout frameworks rather than specific Angular directives like ngClass.