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Your Reducer is a function that accept two values and return state but since you decorated your app with ActionReducerMap that's mean you should provide ActionReducer<> instead of normal a function.

Solution 1 Simply remove ActionReducerMap from your appReducer and it should work. note that NgRx start changing the way you write your state,action,effects,selectors and reducer. the newer method of declaring the state is the one that use ActionReducerMap here is a good article regarding the topic (Look at second solution)

Solution 2 update your ngrx state files to use the new method provided by NgRx like following:

recipes.actions.ts