title: Splitting big reducer into smaller reducers
body: <p>I have a feature reducer (slice reducer) called animals. I want to split these reducers to mammals, birds, fishes etc. This part is easy as I can simply use the <code>ActionReducerMap</code>. </p>
  
  <p>Now let's say the mammals' reducer's state is huge and I want to split it to several smaller reducers i.e cat's family, dog's family etc. the ActionReducerMap is not returning a reducer and is not nestable. I tried searching the web for solution or example but I couldn't find. My question, in short, is how to make multi-level nested reducers.</p>
  
  <pre><code>export interface AnimalsState{
    mammals: fromMammals.mammalsState;
    birds: fromBirds.birdsState;
  }
  
  export const reducers: ActionReducerMap&lt;AnimalsState&gt; = {
    mammals: fromMammals.reducer,
    birds: fromBirds.reducer
  };
  </code></pre>
  
  <p>I want to split mammals reducer into smaller reducers.</p>