Learn the basics of rendering elements in React. Elements are the fundamental building blocks of React applications. Unlike browser DOM elements, React elements are lightweight plain objects and are efficient to create. React DOM handles the task of updating the actual DOM to match these React elements.
Rendering an Element into the DOM
Discover how to render a React element into the DOM. In React, you typically have a single root DOM node within your HTML file, and everything inside it is managed by React DOM. Learn how to use ReactDOM.createRoot() to define the root DOM node and how to use root.render(element) to render a React element within it. This fundamental process is illustrated with a “Hello, world” example.
Updating the Rendered Element
Explore how React handles updates to rendered elements. React elements are immutable, meaning their children or attributes cannot be changed once they are created. To update the UI, you must create a new element and pass it to root.render(). This concept is demonstrated using a ticking clock example, where the UI updates every second by calling root.render(element) within a setInterval() callback.
React Only Updates What’s Necessary
Learn about React’s efficient update mechanism. React DOM compares the current element and its children to the previous one, applying only the necessary updates to bring the DOM to the desired state. This efficient approach minimizes unnecessary DOM manipulations. You can inspect this behavior using browser tools, where you’ll see that only the changed parts of the UI get updated by React DOM. This strategy promotes thinking about the desired UI state at any given moment rather than focusing on how to change it over time, reducing potential bugs in your code.
Components enable you to break down your UI into independent, reusable building blocks, each isolated and focused. Discover how components in React are conceptually similar to JavaScript functions. They accept inputs called “props” and return React elements that define what should appear on the screen. This guide introduces both function and class components, explaining how to render them and how to compose and extract components for better code organization and reusability. Additionally, it emphasizes the read-only nature of props in React components and the importance of keeping components pure with respect to their props.
Learn how to handle events in React, which closely resembles handling events on DOM elements. This guide explains the syntax differences, such as using camelCase for event names and passing functions as event handlers in JSX. It highlights that you must explicitly call preventDefault() to prevent default behavior in React events. The guide introduces the concept of synthetic events, which are created by React and follow the W3C spec, ensuring cross-browser compatibility. It also emphasizes that event listeners should be provided when elements are initially rendered in React, eliminating the need for addEventListener. The guide covers event handling in class components, emphasizing the importance of binding event handler methods to the class instance to avoid issues with this. It provides solutions for properly binding event handlers, including using arrow functions or class fields syntax. Finally, the guide explains how to pass extra parameters to event handlers, demonstrating two equivalent methods: using arrow functions or Function.prototype.bind.
This guide introduces the concept of utility-first design using Tailwind CSS, emphasizing the shift from traditional CSS-based styling to directly applying pre-existing utility classes in HTML. It provides an example of styling a chat notification component with both traditional CSS and Tailwind CSS. The guide showcases how Tailwind CSS classes can be used to control layout, sizing, colors, and other styling aspects in a more concise manner. It explains the benefits of this approach, such as reducing the need for custom class names, preventing CSS bloat, and making changes safely. The guide also highlights the advantages of utility classes over inline styles, including the ability to work with design constraints, create responsive designs, and style hover and focus states. Finally, it addresses maintainability concerns by recommending component extraction and the use of editor features for managing repeated utility combinations.
This guide introduces Next.js, a React framework that simplifies web application development. It addresses common challenges such as bundling, code splitting, pre-rendering, and server-side rendering, offering an excellent developer experience. Next.js features include intuitive routing, automatic code splitting, CSS support, Fast Refresh, and API endpoints. The tutorial walks through building a basic blog app to teach Next.js fundamentals and assumes prior knowledge of JavaScript and React. Users can seek help and discuss Next.js on the Discord community.