Learn React JS: Your Comprehensive Guide to Success

Learn React Js, a powerful JavaScript library for building user interfaces, with our comprehensive guide. This guide, brought to you by learns.edu.vn, will walk you through the essential concepts, providing you with the knowledge and skills to create dynamic and interactive web applications. Whether you’re a beginner or an experienced developer, discover how React JS can revolutionize your approach to front-end development.

1. Introduction to React JS

React JS is a declarative, efficient, and flexible JavaScript library for building user interfaces (UIs). It allows developers to create reusable UI components, making it easier to manage and update complex applications. React is maintained by Facebook and a large community of developers, ensuring continuous improvement and a wealth of resources for learners. Mastering React fundamentals, component-based architecture, and JSX syntax opens doors to a fulfilling career in web development.

1.1. What is React JS?

React JS is not a framework but a library focused specifically on the view layer of an application, which is responsible for rendering the UI. This focused approach allows React to be highly efficient and flexible, enabling developers to integrate it into existing projects or build new ones from scratch.

1.2. Why Learn React JS?

There are several compelling reasons to learn React JS:

• Component-Based Architecture: React promotes a component-based approach, where UIs are broken down into reusable components. This makes code easier to manage, test, and reuse.
• Virtual DOM: React uses a virtual DOM (Document Object Model) to optimize updates to the actual DOM. This results in faster rendering and improved performance.
• JSX: React uses JSX, a syntax extension to JavaScript that allows you to write HTML-like code within JavaScript. This makes UI development more intuitive and efficient.
• Large Community and Ecosystem: React has a large and active community, which means there are plenty of resources, libraries, and tools available to help you learn and build applications.
• Job Opportunities: React is one of the most in-demand front-end technologies, so learning React can significantly increase your job prospects.

1.3. Key Features of React JS

• Declarative: React makes it easy to reason about your application and aims to minimize side effects.
• Component-Based: Build encapsulated components that manage their own state, then compose them to make complex UIs.
• Learn Once, Write Anywhere: React can render on the server using Node and power mobile apps using React Native.
• Virtual DOM: React uses a virtual DOM to optimize updates to the actual DOM, improving performance.
• JSX: React uses JSX, a syntax extension to JavaScript that allows you to write HTML-like code within JavaScript.

1.4. Understanding React’s Purpose

React JS primarily addresses the challenge of building dynamic and interactive user interfaces efficiently. It provides tools and patterns to manage the complexity of UI development, making it easier to create and maintain large-scale applications. By focusing on reusable components and efficient updates, React helps developers build UIs that are both performant and maintainable. The demand for React developers is soaring, promising excellent career prospects and competitive salaries. (Source: Indeed).

2. Setting Up Your Development Environment for React JS

Before you start learning React, you need to set up your development environment. This involves installing Node.js, npm (Node Package Manager), and a code editor.

2.1. Installing Node.js and npm

Node.js is a JavaScript runtime environment that allows you to run JavaScript code outside of a web browser. npm is a package manager that comes with Node.js and is used to install and manage dependencies for your projects.

• Download Node.js: Go to the official Node.js website and download the installer for your operating system.

• Install Node.js: Run the installer and follow the instructions. Make sure to select the option to add Node.js to your PATH environment variable.

• Verify Installation: Open a command prompt or terminal and run the following commands:

  node -v
  npm -v

  These commands should display the versions of Node.js and npm installed on your system.

2.2. Choosing a Code Editor

A code editor is a software application that allows you to write and edit code. There are many code editors available, but some of the most popular choices for React development include:

• Visual Studio Code (VS Code): A free, lightweight, and powerful code editor with excellent support for JavaScript and React.
• Sublime Text: A popular code editor known for its speed and extensibility.
• Atom: A free and open-source code editor developed by GitHub.

Choose a code editor that you are comfortable with and that meets your needs.

2.3. Creating Your First React App

The easiest way to create a new React app is to use Create React App, a tool that sets up a modern React development environment for you.

• Install Create React App: Open a command prompt or terminal and run the following command:

  npm install -g create-react-app

• Create a New App: Navigate to the directory where you want to create your app and run the following command:

  create-react-app my-first-app

  Replace my-first-app with the name of your app.

• Start the App: Navigate to the app directory and run the following command:

  cd my-first-app
  npm start

  This will start the development server and open your app in a web browser.

2.4. Understanding the Project Structure

A typical React project created with Create React App has the following structure:

my-first-app/
  node_modules/
  public/
    index.html
    favicon.ico
  src/
    App.js
    index.js
    App.css
    index.css
  package.json
  README.md

• node_modules/: Contains the dependencies for your project.
• public/: Contains static assets such as index.html and favicon.ico.
• src/: Contains the source code for your app, including JavaScript and CSS files.
• package.json: Contains metadata about your project, including dependencies and scripts.
• README.md: Contains documentation for your project.

This structure ensures that your project is well-organized and easy to maintain. Create React App offers a streamlined setup process, allowing you to focus on coding rather than configuration. (Source: Create React App Documentation).

3. Understanding Components in React JS

Components are the building blocks of React applications. They are reusable pieces of UI that can be composed together to create complex UIs.

3.1. What are Components?

A component is a JavaScript function that returns JSX (or React elements) describing what should appear on the screen. Components can be as small as a button or as large as an entire page.

3.2. Functional Components vs. Class Components

There are two types of components in React: functional components and class components.

• Functional Components: Are simple JavaScript functions that accept props as an argument and return JSX. They are the preferred way to write components in modern React.

  function MyComponent(props) {
    return (
      <h1>Hello, {props.name}</h1>
    );
  }

• Class Components: Are JavaScript classes that extend the React.Component class. They have access to state and lifecycle methods, but are less commonly used in modern React.

  class MyComponent extends React.Component {
    render() {
      return (
        <h1>Hello, {this.props.name}</h1>
      );
    }
  }

3.3. Creating and Nesting Components

To create a component, simply define a JavaScript function that returns JSX. To nest components, use the component name as an HTML tag within another component.

function MyButton() {
  return (
    <button>Click me</button>
  );
}

function MyApp() {
  return (
    <div>
      <h1>Welcome to my app</h1>
      <MyButton />
    </div>
  );
}

export default MyApp;

In this example, MyButton is nested inside MyApp. When MyApp is rendered, it will also render MyButton.

3.4. Props: Passing Data to Components

Props (properties) are used to pass data from a parent component to a child component. Props are read-only and cannot be modified by the child component.

function MyComponent(props) {
  return (
    <h1>Hello, {props.name}</h1>
  );
}

function MyApp() {
  return (
    <MyComponent name="John" />
  );
}

In this example, the name prop is passed from MyApp to MyComponent. The MyComponent then uses the name prop to render the greeting.

3.5. Component Lifecycle (for Class Components)

Class components have lifecycle methods that allow you to control what happens at different stages of the component’s life. Some common lifecycle methods include:

• componentDidMount(): Called after the component is mounted (inserted into the DOM).
• componentDidUpdate(): Called after the component is updated.
• componentWillUnmount(): Called before the component is unmounted (removed from the DOM).

Functional components can achieve similar functionality using Hooks, such as useEffect.

Understanding components is crucial for building modular and maintainable React applications. Components allow you to break down complex UIs into smaller, manageable pieces, making your code easier to understand and test. (Source: React Documentation on Components).

3.6. Component Reusability

Component reusability is one of the core benefits of using React JS. By creating components that are self-contained and reusable, you can significantly reduce the amount of code you need to write and maintain. This not only saves time but also makes your application more consistent and easier to update.

3.7. Best Practices for Component Design

• Single Responsibility Principle: Each component should have a single, well-defined purpose.
• Keep Components Small: Smaller components are easier to understand, test, and reuse.
• Use Descriptive Names: Choose names that clearly indicate the component’s purpose.
• Document Your Components: Add comments to explain how the component works and how to use it.

4. JSX: Writing Markup in React JS

JSX (JavaScript XML) is a syntax extension to JavaScript that allows you to write HTML-like code within JavaScript. It is not required to use React, but it makes UI development more intuitive and efficient.

4.1. What is JSX?

JSX allows you to write HTML elements in your JavaScript code, making it easier to visualize and structure your UI.

const element = <h1>Hello, world!</h1>;

4.2. Why Use JSX?

• Readability: JSX makes your code more readable and easier to understand.
• Efficiency: JSX allows React to optimize updates to the DOM.
• Familiar Syntax: JSX uses a familiar HTML-like syntax, making it easier for developers to learn and use.

4.3. JSX Rules and Syntax

• Single Root Element: A component must return a single root element. If you need to return multiple elements, wrap them in a <div> or a <>.

  function MyComponent() {
    return (
      <div>
        <h1>Hello</h1>
        <p>World</p>
      </div>
    );
  }

• JSX Tags Must Be Closed: All JSX tags must be closed, either with a closing tag or as a self-closing tag.

  <img src="image.jpg" alt="My Image" />

• Use className Instead of class: In JSX, use className instead of class to specify CSS classes.

  <div className="my-class">Hello</div>

• Embedding JavaScript Expressions: You can embed JavaScript expressions in JSX using curly braces {}.

  function MyComponent(props) {
    return (
      <h1>Hello, {props.name}</h1>
    );
  }

4.4. JSX and HTML Differences

While JSX looks similar to HTML, there are some key differences:

• Attributes: In JSX, attributes are written in camelCase (e.g., onClick instead of onclick).
• Reserved Words: JSX uses className instead of class and htmlFor instead of for to avoid conflicts with JavaScript reserved words.
• Expressions: JSX allows you to embed JavaScript expressions using curly braces {}, which is not possible in HTML.

4.5. JSX Best Practices

• Use a Code Formatter: Use a code formatter like Prettier to automatically format your JSX code.
• Keep JSX Simple: Avoid complex logic in your JSX code. Move complex logic to JavaScript functions.
• Use Comments: Add comments to explain your JSX code.

JSX is a powerful tool that makes UI development in React more intuitive and efficient. By understanding the rules and syntax of JSX, you can write cleaner and more maintainable code. (Source: React Documentation on JSX).

5. Styling React JS Components

Styling is an essential part of creating visually appealing and user-friendly React applications. There are several ways to style React components, including inline styles, CSS stylesheets, and CSS-in-JS libraries.

5.1. Inline Styles

Inline styles are applied directly to the HTML elements in your JSX code. They are defined as JavaScript objects with CSS properties as keys and values as strings.

function MyComponent() {
  return (
    <h1 style={{ color: 'blue', fontSize: '24px' }}>Hello, world!</h1>
  );
}

• Pros:
  • Easy to apply styles dynamically based on component state or props.
  • Styles are scoped to the component.
• Cons:
  • Can become verbose and difficult to manage for complex styles.
  • Not ideal for reusable styles.
  • Pseudo-classes and media queries are not supported.

5.2. CSS Stylesheets

CSS stylesheets are separate files that contain CSS rules for your components. You can import CSS files into your React components and apply styles using CSS classes.

• Create a CSS File: Create a CSS file (e.g., MyComponent.css) and define your styles.

  /* MyComponent.css */
  .my-class {
    color: blue;
    font-size: 24px;
  }

• Import the CSS File: Import the CSS file into your React component.

  import './MyComponent.css';
  
  function MyComponent() {
    return (
      <h1 className="my-class">Hello, world!</h1>
    );
  }

• Pros:

  • Separation of concerns (styles are separate from component logic).
  • Reusable styles.
  • Support for pseudo-classes and media queries.

• Cons:

  • Styles are not scoped to the component by default (can lead to naming conflicts).
  • Not ideal for dynamic styles based on component state or props.

5.3. CSS-in-JS Libraries

CSS-in-JS libraries allow you to write CSS styles in your JavaScript code, often using JavaScript objects. These libraries provide features like scoped styles, dynamic styles, and theming.

Some popular CSS-in-JS libraries include:

• Styled Components: A library that allows you to write CSS styles using template literals.
• Emotion: A library that provides a flexible and performant way to write CSS styles.
• Material UI: A popular UI framework that includes a comprehensive set of styled components.

5.3.1. Using Styled Components

• Install Styled Components:

  npm install styled-components

• Create Styled Components:

  import styled from 'styled-components';
  
  const StyledH1 = styled.h1`
    color: blue;
    font-size: 24px;
  `;
  
  function MyComponent() {
    return (
      <StyledH1>Hello, world!</StyledH1>
    );
  }

• Pros:

  • Scoped styles (styles are automatically scoped to the component).
  • Dynamic styles based on component state or props.
  • Theming support.
  • Improved readability and maintainability.

• Cons:

  • Adds a dependency to your project.
  • Can increase bundle size.
  • Requires learning a new syntax.

5.4. Best Practices for Styling React Components

• Choose the Right Approach: Choose the styling approach that best fits your project’s needs.
• Use a Consistent Style: Use a consistent styling approach throughout your project.
• Keep Styles Organized: Keep your styles organized and easy to maintain.
• Use a Code Formatter: Use a code formatter like Prettier to automatically format your CSS code.

Styling React components is a crucial aspect of creating visually appealing and user-friendly applications. By understanding the different styling approaches and best practices, you can create styles that are both maintainable and scalable. (Source: React Documentation on Styling).

6. Handling Events in React JS

Handling events is an essential part of creating interactive React applications. React provides a way to handle events using event handlers.

6.1. What are Events?

Events are actions or occurrences that happen in the browser, such as a user clicking a button, submitting a form, or hovering over an element.

6.2. React Event Handlers

React event handlers are functions that are called when an event occurs. They are defined as properties on HTML elements in your JSX code.

function MyButton() {
  function handleClick() {
    alert('Button clicked!');
  }

  return (
    <button onClick={handleClick}>Click me</button>
  );
}

In this example, handleClick is an event handler that is called when the button is clicked.

6.3. Passing Event Handlers as Props

You can pass event handlers as props from a parent component to a child component.

function MyButton(props) {
  return (
    <button onClick={props.onClick}>Click me</button>
  );
}

function MyApp() {
  function handleClick() {
    alert('Button clicked!');
  }

  return (
    <MyButton onClick={handleClick} />
  );
}

In this example, handleClick is defined in MyApp and passed as a prop to MyButton.

6.4. Synthetic Events

React uses synthetic events, which are cross-browser wrappers around the browser’s native event system. Synthetic events have the same interface as native events, but they work consistently across all browsers.

6.5. Common React Events

Some common React events include:

• onClick: Called when an element is clicked.
• onChange: Called when the value of an input element changes.
• onSubmit: Called when a form is submitted.
• onMouseOver: Called when the mouse pointer is moved over an element.
• onKeyDown: Called when a key is pressed down.

6.6. Event Handling Best Practices

• Use Descriptive Names: Choose names that clearly indicate the event handler’s purpose.
• Keep Event Handlers Simple: Avoid complex logic in your event handlers. Move complex logic to JavaScript functions.
• Use Synthetic Events: Use React’s synthetic events instead of the browser’s native events.
• Pass Event Handlers as Props: Pass event handlers as props from a parent component to a child component.

Handling events is a crucial aspect of creating interactive React applications. By understanding how to define and use event handlers, you can create applications that respond to user actions and provide a rich user experience. (Source: React Documentation on Handling Events).

7. State Management in React JS

State management is the process of managing the data that changes over time in your React application. React provides several ways to manage state, including the useState Hook, the useReducer Hook, and external state management libraries like Redux and Zustand.

7.1. What is State?

State is data that changes over time in your React application. It can include user input, data fetched from an API, or any other data that affects the UI.

7.2. The useState Hook

The useState Hook is the simplest way to manage state in React. It allows you to declare a state variable and a function to update it.

import { useState } from 'react';

function MyComponent() {
  const [count, setCount] = useState(0);

  function handleClick() {
    setCount(count + 1);
  }

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={handleClick}>Increment</button>
    </div>
  );
}

In this example, count is a state variable that is initialized to 0. The setCount function is used to update the value of count.

7.3. The useReducer Hook

The useReducer Hook is a more advanced way to manage state in React. It is similar to Redux, but it is built into React.

import { useReducer } from 'react';

const initialState = { count: 0 };

function reducer(state, action) {
  switch (action.type) {
    case 'increment':
      return { count: state.count + 1 };
    case 'decrement':
      return { count: state.count - 1 };
    default:
      throw new Error();
  }
}

function MyComponent() {
  const [state, dispatch] = useReducer(reducer, initialState);

  return (
    <div>
      <p>Count: {state.count}</p>
      <button onClick={() => dispatch({ type: 'increment' })}>Increment</button>
      <button onClick={() => dispatch({ type: 'decrement' })}>Decrement</button>
    </div>
  );
}

In this example, reducer is a function that takes the current state and an action and returns the new state. The dispatch function is used to send actions to the reducer.

7.4. External State Management Libraries

External state management libraries like Redux and Zustand provide more advanced features for managing state in large applications.

• Redux: A predictable state container for JavaScript apps.

  • Pros:
    • Centralized state management.
    • Predictable state updates.
    • Middleware support.
  • Cons:
    • Can be verbose and complex.
    • Requires learning a new API.

• Zustand: A small, fast, and scalable bearbones state-management solution.

  • Pros:
    • Simple and easy to use.
    • Minimal boilerplate.
    • Scalable.
  • Cons:
    • Less mature than Redux.
    • Fewer features.

7.5. State Management Best Practices

• Keep State Local: Keep state as close as possible to the components that need it.
• Use the useState Hook: Use the useState Hook for simple state management.
• Use the useReducer Hook: Use the useReducer Hook for more complex state management.
• Consider External Libraries: Consider using external state management libraries for large applications.

State management is a crucial aspect of building complex React applications. By understanding the different state management options and best practices, you can create applications that are both maintainable and scalable.

7.6. Global State Management

Global state management involves managing state that is accessible to multiple components throughout your application. This is particularly useful for data that needs to be shared across different parts of the UI. Libraries like Redux and Zustand are designed to handle global state effectively.

7.7. Context API

React’s Context API provides a way to pass data through the component tree without having to pass props manually at every level. This is useful for sharing values like theme settings or user authentication status.

8. Conditional Rendering in React JS

Conditional rendering is the process of rendering different UI elements based on certain conditions. React provides several ways to conditionally render elements, including if statements, ternary operators, and logical && operators.

8.1. Using if Statements

You can use if statements to conditionally render elements in your JSX code.

function MyComponent(props) {
  if (props.isLoggedIn) {
    return (
      <h1>Welcome, user!</h1>
    );
  } else {
    return (
      <h1>Please log in.</h1>
    );
  }
}

8.2. Using Ternary Operators

You can use ternary operators to conditionally render elements in a more concise way.

function MyComponent(props) {
  return (
    props.isLoggedIn ? (
      <h1>Welcome, user!</h1>
    ) : (
      <h1>Please log in.</h1>
    )
  );
}

8.3. Using Logical && Operators

You can use logical && operators to conditionally render elements when you only need to render something if a condition is true.

function MyComponent(props) {
  return (
    props.isLoggedIn && <h1>Welcome, user!</h1>
  );
}

8.4. Conditional Rendering Best Practices

• Use if Statements for Complex Logic: Use if statements for complex conditional logic.
• Use Ternary Operators for Simple Logic: Use ternary operators for simple conditional logic.
• Use Logical && Operators for Simple Conditions: Use logical && operators for simple conditions.
• Keep Conditional Logic Simple: Avoid complex logic in your JSX code. Move complex logic to JavaScript functions.

Conditional rendering is a crucial aspect of building dynamic React applications. By understanding the different conditional rendering options and best practices, you can create applications that respond to user actions and provide a rich user experience.

9. Rendering Lists in React JS

Rendering lists is a common task in React applications. React provides a way to render lists using the map() function.

9.1. Using the map() Function

The map() function is used to transform an array of data into an array of React elements.

function MyComponent(props) {
  const items = props.items.map(item => (
    <li key={item.id}>{item.name}</li>
  ));

  return (
    <ul>{items}</ul>
  );
}

In this example, the map() function is used to transform an array of items into an array of <li> elements.

9.2. Keys

When rendering lists, you need to provide a unique key prop to each element. The key prop helps React identify which items have changed, been added, or been removed.

function MyComponent(props) {
  const items = props.items.map(item => (
    <li key={item.id}>{item.name}</li>
  ));

  return (
    <ul>{items}</ul>
  );
}

In this example, the key prop is set to the id of each item.

9.3. Rendering Lists Best Practices

• Use the map() Function: Use the map() function to transform an array of data into an array of React elements.
• Provide a Unique Key Prop: Provide a unique key prop to each element in the list.
• Keep List Rendering Simple: Avoid complex logic in your JSX code. Move complex logic to JavaScript functions.

Rendering lists is a common task in React applications. By understanding how to use the map() function and provide unique key props, you can create applications that display data in a clear and organized way.

10. Working with Forms in React JS

Forms are an essential part of many web applications. React provides a way to handle forms using controlled components.

10.1. Controlled Components

In React, a controlled component is a component whose value is controlled by React state. This means that the component’s value is always kept in sync with the state.

import { useState } from 'react';

function MyComponent() {
  const [name, setName] = useState('');

  function handleChange(event) {
    setName(event.target.value);
  }

  return (
    <input type="text" value={name} onChange={handleChange} />
  );
}

In this example, the value of the input element is controlled by the name state variable. The handleChange function is called when the value of the input element changes, and it updates the name state variable with the new value.

10.2. Handling Form Submission

To handle form submission, you can use the onSubmit event handler on the <form> element.

import { useState } from 'react';

function MyComponent() {
  const [name, setName] = useState('');

  function handleChange(event) {
    setName(event.target.value);
  }

  function handleSubmit(event) {
    event.preventDefault();
    alert(`Name: ${name}`);
  }

  return (
    <form onSubmit={handleSubmit}>
      <input type="text" value={name} onChange={handleChange} />
      <button type="submit">Submit</button>
    </form>
  );
}

In this example, the handleSubmit function is called when the form is submitted. The event.preventDefault() method is used to prevent the default form submission behavior.

10.3. Form Validation

Form validation is the process of verifying that the data entered into a form is valid. React does not provide built-in form validation, but you can use external libraries like Formik and Yup to simplify the process.

10.4. Working with Forms Best Practices

• Use Controlled Components: Use controlled components to manage the value of form elements.
• Handle Form Submission: Handle form submission using the onSubmit event handler.
• Validate Form Data: Validate form data to ensure that it is valid.
• Provide User Feedback: Provide user feedback to indicate whether the form data is valid or invalid.

Working with forms is an essential part of building interactive web applications. By understanding how to use controlled components, handle form submission, and validate form data, you can create forms that are both user-friendly and secure.

11. Hooks in React JS

Hooks are a new addition in React 16.8. They let you use state and other React features without writing a class.

11.1. What are Hooks?

Hooks are functions that let you “hook into” React state and lifecycle features from function components. Hooks don’t work inside classes — they let you use React without classes.

11.2. Why Use Hooks?

• Reusability: Hooks make it easier to reuse stateful logic between components.
• Readability: Hooks make your code more readable and easier to understand.
• Simplicity: Hooks simplify complex components by breaking them down into smaller, more manageable functions.

11.3. Common React Hooks

Some common React Hooks include:

• useState: Lets you add React state to function components.
• useEffect: Lets you perform side effects in function components.
• useContext: Lets you subscribe to React context without introducing nesting.
• useReducer: An alternative to useState. Accepts a reducer of type (state, action) => newState, and returns the current state paired with a dispatch method.
• useCallback: Returns a memoized version of the callback function that only changes if one of the inputs has changed.
• useMemo: Returns a memoized value that only recomputes when one of the inputs has changed.
• useRef: Returns a mutable ref object whose .current property is initialized to the passed argument (initialValue). The returned object will persist for the full lifetime of the component.
• useImperativeHandle: Customizes the instance value that is exposed to parent components when using ref.
• useLayoutEffect: Is a version of useEffect that fires synchronously after all DOM mutations. Use this to read layout from the DOM and synchronously re-render. Updates scheduled inside useLayoutEffect will be flushed synchronously, before the browser has a chance to paint.
• useDebugValue: Can be used to display a label for custom hooks in React DevTools.

11.4. Custom Hooks

You can create your own custom Hooks to reuse stateful logic between components.

import { useState, useEffect } from 'react';

function useMyHook() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    document.title = `Count: ${count}`;
  }, [count]);

  return [count, setCount];
}

function MyComponent() {
  const [count, setCount] = useMyHook();

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

In this example, useMyHook is a custom Hook that manages the count state variable and updates the document title.

11.5. Hooks Best Practices

• Only Call Hooks at the Top Level: Don’t call Hooks inside loops, conditions, or nested functions.
• Only Call Hooks from React Functions: Call Hooks from React function components or custom Hooks.
• Use Descriptive Names: Choose names that clearly indicate the Hook’s purpose.
• Keep Hooks Simple: Avoid complex logic in your Hooks. Move complex logic to JavaScript functions.

Hooks are a powerful addition to React that make it easier to reuse stateful logic between components and simplify complex components. By understanding the different Hooks and best practices, you can create applications that are both maintainable and scalable.

12. React Router: Navigation in React JS

React Router is a standard library for routing in React. It enables navigation among views in a React application, allowing you to build single-page applications with multiple routes.

12.1. What is React Router?

React Router is a collection of navigational components that compose declaratively with your application. Whether you want to have bookmarkable URLs for your web app or a composable way to navigate in React Native, React Router works wherever React is rendering.

12.2. Why Use React Router?

• Declarative Routing: React Router allows you to define routes declaratively, making it easy to understand and maintain your application’s navigation.
• Dynamic Routing: React Router supports dynamic routing, allowing you to create routes that depend on data or user input.
• Nested Routing: React Router supports nested routing, allowing you to create complex navigation hierarchies.
• History Management: React Router manages the browser history