Writing React from Scratch

• next.js resource
  • https://nextjs.org/learn/react-foundations/getting-started-with-react

import React from "react";
import ReactDOM from "react-dom/client";
 
function App() {
  return <h1>Hello React!</h1>;
}
 
// React v18
const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(<App />);
 
// React before 18 (and also remove /client above)
React.render(<App />, document.getElementById("root"))
 

• ReactDOM
  • ReactDOM is **React’s library for interacting with the DOM.
  • It provides methods to render React components into the actual HTML page.
  • In React 18, the recommended way to render an app is using createRoot.
  • document.getElementById("root") selects the HTML element where React will render your app
• root.render(<App />);
  • renders your React component (<App />) inside the root element

Strictmode

• root.render(<React.StrictMode> <App /> </React.StrictMode>);
• StrictMode is a component that’s part of React
• during development, it will render all components TWICE in order to find any bugs + React will check if we’re using outdated parts of the React API
• good idea to activate it when developing React applications