We will connect to this server later on in the front-end in order to transfer sockets. That’s all we’ll add to the server for now. If you go to “ you won’t see anything because this is just the server we haven’t done the front end of our project yet. Once we have this, you can test it by running: node server.js Should Return: Listening on port 4001 Lastly, we set our server to listen on port 4001. Next, we set io to a socket with the instance of our server. For now, we'll use an instance of the built-in button component as our React element.So, we are creating a server with http.createServer with the express application as the only argument. The function signature is render(element, node), where the first argument is a React element (more on this soon) and the second is the DOM node we chose to render into. If we have a node with id='app', for example, we can get a reference to it with document.querySelector('#app'). React can't render into the body node, but we can choose any node within the body. We should choose a node without any existing children, or assume that any existing children will be replaced. Then we must choose a DOM node in our app to render our React elements into. After that, we can import it in our code: import from 'react-dom' To use React DOM, we first need to install react-dom from npm. These different capitalizations all refer to the same thing. The package name is react-dom on npm, but we often write it as ReactDOM in our JavaScript code and 'React DOM' outside of code. The main API we'll use is the render function it exports. We use the React DOM library for rendering React elements in the browser. In order to see our React elements on the screen, we need to render them with a platform-specific rendering library.

React express