We will now evolve Example2 once again and refactor some of the code that was defined at the component level into an Angular service.
A service is a TypeScript class that has a decorator called Injectable without any parameters that allows the service to be part of the dependency injection (DI) mechanism in Angular 2. DI will ensure that a service instance will be created only once per application, and this instance will be injected in any class that declares it as a dependency in their constructor declarations. Apart from the specific decorator, a service needs to be declared as a provider usually in a module definition, but it can also be declared in component, directive, or pipe definitions. Before jumping ...
