ReactDOMServer is a package provided by React that allows you to render React components to static HTML on the server side. It is mainly used for Server-Side Rendering (SSR), which helps in improving the performance of web applications and enhancing SEO (Search Engine Optimization).

When you use ReactDOMServer, you can pre-render your React components into HTML strings before sending them to the browser. This way, the user can see the fully rendered content immediately, even before JavaScript loads and becomes interactive.

ReactDOMServer provides two primary methods:

• renderToString():
  • Renders a React element to its initial HTML.
  • This HTML can then be sent to the client and "hydrated" (attach event listeners) once React loads in the browser.
• renderToStaticMarkup():
  • Similar to renderToString(), but it does not include extra attributes like data-reactroot.
  • Useful when you don't need to make the HTML interactive (e.g., rendering static content like emails).

Example:

import ReactDOMServer from 'react-dom/server';
import App from './App';

const htmlString = ReactDOMServer.renderToString(<App />);
console.log(htmlString);

Use Cases of ReactDOMServer:

• Server-Side Rendering (SSR) for better SEO and faster initial load.
• Static site generation.
• Generating HTML content for emails.
• Pre-rendering components outside the browser environment.

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