Angular Interview Practice

In Angular, a service is provided using the @Injectable decorator. This decorator is essential as it marks a class as available for dependency injection, indicating that the class can be instantiated by the Angular framework and injected into other components or services.

When you apply the @Injectable decorator to a service, it enables the Angular injector system to manage the lifecycle of the service instance. This includes creating a singleton instance (if specified) or ensuring that a new instance is created as needed. The service can then be used within components, other services, or directives, effectively promoting code reusability and a clear separation of concerns.

While declaring a service in a module and specifying it as a provider is also a part of making it available (which relates to the context in which the service can be used), the fundamental requirement to indicate that a class can be injected is the use of the @Injectable decorator. The other options presented do not correctly capture the fundamental mechanism by which a service is defined as injectable within the Angular framework. It’s the @Injectable decorator that first and foremost prepares a service for this role, enabling effective and efficient dependency injection in Angular applications.