Warning: Rendering <Context.Consumer.Consumer> is not supported and will be removed in a future major release. Did you mean to render <Context.Consumer> instead?
Error: Invariant failed: You should not use <Link> outside a <Router>
    at invariant (/Users/aiancheng/Documents/react/ssr_react/node_modules/tiny-invariant/dist/tiny-invariant.cjs.js:13:11)
    at Object.children (/Users/aiancheng/Documents/react/ssr_react/node_modules/react-router-dom/cjs/react-router-dom.js:190:18)
    at recursive (/Users/aiancheng/Documents/react/ssr_react/node_modules/react-tree-walker/dist/react-tree-walker.js:129:41)
    at /Users/aiancheng/Documents/react/ssr_react/node_modules/react-tree-walker/dist/react-tree-walker.js:153:26
    at process._tickCallback (internal/process/next_tick.js:68:7)

如上问题为： 将3-8章节， 给webpack.config.server.js添加externals， 在dev-static.js修改module引入方法， 即变更为getModuleFromString方法， 然后变更相关方法获取module之后执行服务端代码，就会报上面的错误。 找了好久没找到原因， 还请老师帮忙看一下。