问题

I'm trying to render react isomorphicaly, and it renders but I get the Warning/Error in client saying:

I'm using jspm and npm as package managers;

warning.js:25 Warning: render(...): Replacing React-rendered children with a new root component. If you intended to update the children of this node, you should instead have the existing children update their state and render the new components instead of calling ReactDOM.render.

The source outputed by server renderToString:

<div id="reactRoot"><div data-reactroot="" data-reactid="1" data-react-checksum="845161664"><marquee data-reactid="2"><h1 data-reactid="3">App</h1></marquee></div></div>

The source replaced by react after render:

<div id="reactRoot"><div data-reactid=".0"><marquee data-reactid=".0.0"><h1 data-reactid=".0.0.0">App</h1></marquee></div></div>

The express server middleware:

import App from './components/App/App.jsx';
// [...] Express code removed for brevity
app.use('*', (req, res, next) => {
  try {
    res.render('index.html', {
      reactHtml: renderToString(
        <App />
      )
    });
  } catch (err) {
    next(err);
  }
});

The index.html:

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>App</title>
  <script>
    console.log('Running on <%- @env %> environment!');
    <% if (@env == 'development') : %>
    System.import('systemjs-hot-reloader/default-listener.js');
    <% end %>
    System.import('/app.jsx!')
    .catch(console.error.bind(console));
  </script>
</head>
<body>
  <div id="reactRoot"><%- reactHtml %></div>  
</body>
</html>

I'm using ect as templating engine here;

The app.jsx:

import { render } from 'react-dom';
import App from './components/App/App.jsx';
const mountPoint = document.getElementById('reactRoot');
render(
  <App />,
  mountPoint
);

The App/App.jsx:

import React from 'react';

const App = () => (
  <div>
    <marquee><h1>App</h1></marquee>
  </div>
);

export default App;

回答1:

Use renderToStaticMarkup

// render the dynamic code of the page to a string.
var appHtml = React.renderToString(<Application/>);

// now use React as a static templating language to create the <html>, 
// <head>, and <body> tags
var fullPageHtml = React.renderToStaticMarkup(<HtmlPage content={appHtml}/>);

res.write(fullPageHtml);

Full Issue resolution discussion can be found here. https://github.com/aickin/react-dom-stream/issues/4

来源：https://stackoverflow.com/questions/36653557/react-server-rendering-replacing-react-rendered-children-with-a-new-root-com

标签

javascript

reactjs

server-rendering

React server rendering --> Replacing React-rendered children with a new root component

问题

回答1:

Use renderToStaticMarkup