React Redux unexpected key passed to create store : <p>I am getting the error <code>Unexpected key "characters" found in initialState argument passed to createStore. Expected to find one of the known reducer keys instead: "marvelReducer", "routing". Unexpected keys will be ignored.</code> </p>

<p>rootReducer : </p>

<pre><code> import { combineReducers } from 'redux';
 import { routerReducer } from 'react-router-redux';
 import marvelReducer from './marvelReducer';

 const rootReducer = combineReducers({
   marvelReducer,
   routing: routerReducer
 });
 export default rootReducer;
</code></pre>

<p>marvelReducer : </p>

<pre><code>import { FETCH_MARVEL } from '../constants/constants';
import objectAssign from 'object-assign';

export default function marvelReducer(state = [], action) {
  switch (action.type) {
    case FETCH_MARVEL:
      return objectAssign({}, state, {characters: action.data});

    default:
      return state;
  }
}
</code></pre>

<p>store : </p>

<pre><code>import { createStore } from 'redux';
import { syncHistoryWithStore } from 'react-router-redux';
import { browserHistory } from 'react-router';

import rootReducer from '../reducers/index';

const initialState = {
  characters: []
};

const store = createStore(rootReducer, initialState);

export const history = syncHistoryWithStore(browserHistory, store);

if (module.hot) {
  module.hot.accept('../reducers/', () =&gt; {
    const nextRootReducer = require('../reducers/index').default;
    store.replaceReducer(nextRootReducer);
  });
}

export default store;
</code></pre>

<p>I have very similar code in another application and it's working fine. Not sure what's going on here</p>
