title: Warning: Unexpected key " A" found in previous state received by the reducer
body: <p>I am adding the component dynamically with the help of <code>require.ensure()</code> of ES6 and the <code>getComponent()</code> of the <code>react-router</code>. I am getting the above error once I am opening separate tab for the each record having the same key for example "A". My dynamic Loading is like this:</p>
  
  <pre><code> require.ensure([], (require) =&gt; { 
       const req = require('./components/A).default 
       const reducer= require('./modules').default
       injectReducer(store, {
           key: 'A',
           reducer
       })
       cb(null, req)
   })
  </code></pre>
  
  <p>My code for the <code>createstore()</code> is like this:</p>
  
  <pre><code>export const makeRootReducer = (asyncReducers) =&gt; {
    return combineReducers({
      B,
      C,
      ...asyncReducers
    })
  }
  export const injectReducer = (store, { key, reducer }) =&gt; {
    if (Object.hasOwnProperty.call(store.asyncReducers, key))return
    store.asyncReducers[key] = reducer
    store.replaceReducer(makeRootReducer(store.asyncReducers))
  }
  </code></pre>
  
  <p>Now the issue is that on browser tab opening except the first time it is showing the warning as: </p>
  
  <blockquote>
    <p>Unexpected key " A" found in previous state received by the reducer Expected to find one of the known reducer keys instead: "B", "C". Unexpected keys will be ignored.</p>
  </blockquote>
  
  <p>If I will pass initially Key 'A' <code>combineReducers()</code> then this warning will go off. But this <code>combineReducers()</code> is global and it will keep the state of the reducers so that I don't want to pass this Key on the initial load. How can I solve this warning please assist me.</p>