React Components

React is a JavaScript library for building user interfaces. In React, components are the building blocks that encapsulate the logic and structure of a user interface. They are reusable and can be composed together to create complex UIs.

There are two types of React components:

1. Functional Components: These are simple JavaScript functions that receive props (input data) as arguments and return JSX (a syntax extension for JavaScript) to describe the component’s output. Functional components are easier to read, test, and reason about, and they are preferred for most use cases.

Example of a functional component:

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

2. Class Components: These are ES6 classes that extend the React.Component base class. Class components have more features and are necessary for advanced scenarios such as maintaining local state, lifecycle methods, and handling user interactions. However, with the introduction of React Hooks in React 16.8, functional components can also handle these functionalities.

Example of a class component:

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

Both functional and class components can be rendered within other components or directly in the application’s root component. React components follow a unidirectional data flow, where data flows from parent components to child components through props.

Components can have their own state, which is managed and updated internally within the component. State allows components to handle dynamic data and trigger re-rendering when the state changes. Class components can define and modify state using the this.state property, while functional components can use the useState hook to achieve the same behavior.

React components are reusable and can be composed together to build complex user interfaces. They promote modularity, reusability, and maintainability in React applications.