title: In Typescripted Redux, how do I find my root reducer's type?
body: <pre class="lang-js prettyprint-override"><code>export const makeStore = () =&gt; {
    const store = configureStore({
      reducer: {
        reducer,
        growthReportSlice,
        selectBarSlice,
      },
      ....
    return store;
  };
  const dummy = makeStore();
  
  export const wrapper = createWrapper(makeStore, { debug: true });
  export type AppDispatch = typeof dummy.dispatch;
  // export type RootReducer = ReturnType&lt;typeof reducer&gt; &amp;
  //   ReturnType&lt;typeof growthReportSlice&gt; &amp;
  //   ReturnType&lt;typeof selectBarSlice&gt;;
  export const useAppDispatch = () =&gt; useDispatch&lt;AppDispatch&gt;();
  </code></pre>
  <p>I just need the ReturnType of the root reducer but I have 3 reducers combined. How can I get the correct typing?</p>