Understanding React.js: Features and Benefits Explained

React Components and JSX

React components are the heart of React.js. A component is a self-contained unit that encapsulates its logic, state, and rendering process. Understanding the Scope of Web Development helps put the role of React components into perspective, especially as front-end technologies continue to evolve. Components can be functional or class-based, but functional components are now more commonly used due to the introduction of React Hooks.

Functional Components: These are simpler components that are written as JavaScript functions. Functional components receive props as arguments and return JSX. With the introduction of hooks in React 16.8, functional components can now manage state and handle lifecycle events, making them as powerful as class components.

• Class Components: These are ES6 classes that extend React. Each component requires a render() method to return JSX. Class components can hold and manage state and lifecycle events using the componentDidMount and shouldComponentUpdate methods.
Example:
• Class Welcome extends React.
• Component {
• render() {
• return Hello, {this.props.name};
• }
• }

JSX Syntax: JSX allows you to write HTML-like code within JavaScript. Using JSX in React is not mandatory, but it provides a cleaner and more readable syntax. JSX is eventually compiled into React.createElement() calls.

Example:
• const element = Hello, world!;
• JSX also allows you to embed JavaScript expressions within curly braces {}:
• const user = ‘John’;
• const element = Hello,
• {user}!;



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State and Props in React

In React, data is passed between components through props and state.

Props: Props (short for properties) are read-only and used to pass data from a parent component to a child component. They are immutable, meaning the child component cannot change them.

Example:

• function Greeting(props) {
• return Hello, {props.name}!;
• }

State: State is used to store data that changes over time. Unlike props, the state is mutable and can be modified within a component. The state typically tracks user interactions, form inputs, or any other dynamic data in an app.

Example using hooks:

The Counter function is a simple React component that uses a state hook to track the number of times a button is clicked. It initializes a state variable count with a starting value of 0 using useState. For those aiming to build real-world projects and validate their skills, earning a Web Developer Certification can be a valuable step. Inside the returned JSX, it displays the current count in a paragraph and includes a button labeled “Click me.” When the button is clicked, it triggers an event handler that updates the count by incrementing it by one using the setCount function. This causes the component to re-render and display the updated count. However, the code contains a few syntax errors, such as estate(0) instead of useState(0) and set count instead of setCount. Correcting these issues will ensure the component functions as intended.




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React Hooks

React hooks allow functional components to manage state and side effects (e.g., data fetching or event listeners). Introduced in React 16.8, hooks have become the standard for writing React components.

useState: The useState hook allows you to add state to functional components.

const [state, setState] = useState(initialState);

useEffect: The useEffect hook handles side effects, such as fetching data or subscribing to a service, within functional components.

• useEffect(() => {
• //Code to run on component mount
• },
• [dependencies]);

Custom Hooks: Custom hooks allow you to reuse logic across components. A custom hook is a function that uses built-in hooks like useState and useEffect. If you’re preparing for job opportunities, having a well-crafted Full Stack Developer Resume can make a strong impression. React Router: React Router is a popular library for navigation in React applications. It allows you to create single-page applications with multiple views by defining routes and linking them to different components.



React Router

React Router: You can install React Router with the following:

#npm install react-router-dom

Creating Routes: Define routes using components and manage navigation using or components.

Nested Routing: React Router also supports nested routing, which allows you to create hierarchical navigation structures.

React Router’s nested routing feature enables the creation of structured, hierarchical navigation. This allows you to define routes inside parent routes, making it ideal for layouts with shared components like headers or sidebars. Before diving into routing and other advanced features, it’s important to complete initial setup steps like Downloading Node.js and NPM which are essential for running React projects. For example, in a dashboard, the main layout can remain constant while different subcomponents render based on the nested route. This helps maintain consistent UI and improves the flow of your app. Nested routes keep the structure clean and scalable, especially when dealing with complex applications. By using components like , you can specify where child routes should render within the parent layout. This modular approach enhances user experience and simplifies route management as your project grows.

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React Best Practices and Performance Optimization

Code Splitting: Code splitting allows you to load parts of your application only when needed, improving initial load time and overall performance. React supports code splitting using React.lazy() and Suspense.

Memoization: Use React. Memo to optimize functional components by memorizing them. This prevents unnecessary re-renders when props don’t change.

Lazy Loading: React supports lazy loading, which defers the loading of components until they are needed. This improves performance by reducing the initial JavaScript bundle size.

Avoiding Unnecessary Renders: Use shouldComponentUpdate in class components or React to avoid unnecessary renders memo in functional components.