good-action-effect.ts

// great actions allow us to fully 
// understand how data changes and depends 
// on each other in our applciation
const loadTodos$ = createEffect(() => {
  const actions = inject(Actions);
  const todoService = inject(TodoService);
  
  return actions.pipe(
    // this tells us all the situations
    // when a todo list must be refetched
    // according to the business logic
  	ofType(
      TodoActions.todoListComponentLoaded,
      TodoActions.todoSuccessfullyDeleted,
    ),
    switchMap(() => todoService().getTodos().pipe(
    	map(todos => TodoActions.loadTodosSuccess(todos)),
    )),
  ); 
}, {functional: true});

const deleteTodo$ = createEffect(() => {
  const actions = inject(Actions);
  const todoService = inject(TodoService);
  
  return actions.pipe(
    ofType(TodoActions.todoDeletion),
    switchMap(todoId => todoService().deleteTodo(todoId).pipe(
        // here, we only have to notify the application
        // that a todo has been successfully deleted
        // then other parts of the app can react accordingly
        // no tight coupling 
    	map(todos => TodoActions.todoSuccessfullyDeleted(todos)),
    )),
  );
});