old_contents: import { createStore, applyMiddleware } from 'redux';
  import rootReducer from 'reducers/';
  import thunk from 'redux-thunk';
  
  /* Redux middleware that show error when you try to mutate your state either inside a dispatch or between dispatches */
  import reduxImmutableStateInvariant from 'redux-immutable-state-invariant';
  
  export default function configureStore(initialState) {
    return createStore(
      rootReducer,
      initialState,
      // window.__REDUX_DEVTOOLS_EXTENSION__ && window.__REDUX_DEVTOOLS_EXTENSION__(),
      applyMiddleware(thunk, reduxImmutableStateInvariant()),
    );
  }
  
new_contents: import { createStore, applyMiddleware, compose } from 'redux';
  import rootReducer from 'reducers/';
  import thunk from 'redux-thunk';
  
  /* Redux middleware that show error when you try to mutate your state either inside a dispatch or between dispatches */
  import reduxImmutableStateInvariant from 'redux-immutable-state-invariant';
  
  const composeEnhancers =
    typeof window === 'object' &&
    window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ ?   
      window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__({
        // Specify extension’s options like name, actionsBlacklist, actionsCreators, serialize...
      }) : compose;
  
  export default function configureStore(initialState) {
    return createStore(
      rootReducer,
      initialState,
      composeEnhancers(applyMiddleware(thunk, reduxImmutableStateInvariant())),
    );
  }
  
subject: make redux extension work again