What Should You Know About ReactDOMServer?

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What Should You Know About ReactDOMServer?

The ReactDOMServer module in the React ecosystem facilitates the rendering of React components into static HTML. While it’s typically associated with server-side operations, especially in Node.js environments, its methods can also be used in client-side scenarios.

What’s the Significance of Server-Side Rendering (SSR)?

Server-side rendering is a technique where the server pre-renders a web page’s content before sending it to the browser. This has several benefits:

  • Faster Initial Page Load: The browser receives pre-rendered HTML, which it can display almost immediately, enhancing the perceived performance;
  • SEO Benefits: Search engines can easily crawl and index the pre-rendered content, improving the site’s visibility;
  • Consistent Initial State: SSR ensures users get a consistent view of the web page, regardless of their device or network conditions.

Key Methods of ReactDOMServer

There are two primary methods provided by ReactDOMServer:

  • renderToString(): This method returns a string of HTML. It includes React-specific attributes and event listeners, making it suitable for cases where React will attach to the rendered content on the client-side;
  • renderToStaticMarkup(): Returns a string of HTML too, but without the React-specific data attributes. This is useful for cases where the rendered content won’t have further React interactions.
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Practical Example with Express

For instance, when operating a Node-based web server such as Express, Hapi, or Koa, you typically use the renderToString method to convert your main component into a string format and then send it as a response.

Express.js is a popular Node.js framework used for building web applications. By integrating ReactDOMServer, one can easily serve pre-rendered React content. Below is a simple example:

// using Express
import { renderToString } from 'react-dom/server';
import MyPage from './MyPage';

app.get('/', (req, res) => {
  res.write('<!DOCTYPE html><html><head><title>My Page</title></head><body>');
  res.write('<div id="content">');
  res.write(renderToString(<MyPage />));
  res.write('</div></body></html>');
  res.end();
});

Conclusion

ReactDOMServer offers a robust way to harness the power of server-side rendering in React applications. Whether you’re looking to improve performance, SEO, or deliver a consistent user experience, SSR with ReactDOMServer is a tool worth considering. 

You may also like the article about React component re-rendering on browser resize to understand how components respond to viewport changes.

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