具体可查看github 上官方提供的 demo
下面对代码关键地方做说明，主要讲解如何实现数据共享。

with-redux-store 的代码如下

import React from "react";
import { initializeStore } from "../store";

const isServer = typeof window === "undefined";
const __NEXT_REDUX_STORE__ = "__NEXT_REDUX_STORE__";

function getOrCreateStore(initialState) {
  // Always make a new store if server, otherwise state is shared between requests
  if (isServer) {
    return initializeStore(initialState);
  }

  // Create store if unavailable on the client and set it on the window object
  if (!window[__NEXT_REDUX_STORE__]) {
    window[__NEXT_REDUX_STORE__] = initializeStore(initialState);
  }
  return window[__NEXT_REDUX_STORE__];
}

export default App => {
  return class AppWithRedux extends React.Component {
    static async getInitialProps(appContext) {
      // 在这可以把一些服务端请求数据对state进行初始化，如果没有就用下面注释掉的默认方式
      if (isServer) {
        const { req } = appContext.ctx;
        const session = req.session;
        // 根据放到session中的用户数据初始化state
        if (session && session.userInfo) {
          reduxStore = getOrCreateStore({ user: session.userInfo });
        } else {
          reduxStore = getOrCreateStore();
        }
      } else {
        reduxStore = getOrCreateStore();
      }

      // Get or Create the store with `undefined` as initialState
      // This allows you to set a custom default initialState
      //const reduxStore = getOrCreateStore()

      // Provide the store to getInitialProps of pages
      appContext.ctx.reduxStore = reduxStore;

      let appProps = {};
      if (typeof App.getInitialProps === "function") {
        appProps = await App.getInitialProps(appContext);
      }

      return {
        ...appProps,
        initialReduxState: reduxStore.getState(), //获取服务端store中的state，传递给前端的store
      };
    }

    constructor(props) {
      super(props);
      // 创建前端的store实例，前端绑定store时必须使用这个实例，不然新创建的store实例肯定获取不到这个实例的内容，也就会造成state有值，但是就是拿不到
      this.reduxStore = getOrCreateStore(props.initialReduxState);
    }

    render() {
      return <App {...this.props} reduxStore={this.reduxStore} />;
    }
  };
};

在_app.js 中使用

import App from "next/app";
import React from "react";
import withReduxStore from "../lib/with-redux-store";
import { Provider } from "react-redux";

class MyApp extends App {
  render() {
    // 注意，这传给store的对象一定是里面返回的reduxStore这个，不能再重新获取一个
    const { Component, pageProps, reduxStore } = this.props;
    return (
      <Provider store={reduxStore}>
        <Component {...pageProps} />
      </Provider>
    );
  }
}

export default withReduxStore(MyApp);