使用redux form，如何组合initialValues的值？

// formReducer.js

import { combineReducers } from 'redux';
import { reducer as formReducer } from 'redux-form';

const initialValues = {
  // 设置表单字段的初始值
  field1: 'initial value 1',
  field2: 'initial value 2',
  // ...
};

const rootReducer = combineReducers({
  form: formReducer.plugin({
    // 设置表单的initialValues
    formName: (state, action) => {
      return {
        ...state,
        initialValues
      };
    }
  }),
  // 其他的reducer
});

export default rootReducer;

// index.js

import React from 'react';
import ReactDOM from 'react-dom';
import { Provider } from 'react-redux';
import { createStore } from 'redux';
import rootReducer from './formReducer';
import App from './App';

const store = createStore(rootReducer);

ReactDOM.render(
  <Provider store={store}>
    <App />
  </Provider>,
  document.getElementById('root')
);