Component and Its LifeCycle — React

React Js Components

What is a Component?

Components are the building blocks of a React application. A component can be defined as a reusable block of code that divides the user interface into smaller parts.

Each component can manage its own state, receive inputs (called “props” or properties) from its parent component, and return React elements to be rendered in the DOM.

Uses of Components

Uses of Components

Components in React serve several important purposes, making them a fundamental building block of React applications. Here are some of the key uses of components:

Modularity and Reusability: Components allow you to break down your UI into smaller, manageable pieces. These pieces can be reused throughout your application, making it easier to build and maintain complex user interfaces.

Encapsulation: Each component encapsulates its own logic, behavior, and appearance. This means that you can work on different parts of your application in isolation, without affecting other components.

Organization: Components provide a structured way to organize your application’s UI. You can have separate components for headers, footers, navigation menus, forms, buttons, etc.

Maintenance and Debugging: Components make it easier to identify and fix issues in your code. When a component is responsible for a specific part of the UI, it’s easier to locate and address problems.

Testing: Components can be tested independently, which helps ensure that each piece of your UI functions correctly. This is especially valuable for larger applications where manual testing can be time-consuming and error-prone.

Composition: Components can be combined or composed together to create more complex UIs. This allows you to build on top of existing components to create new and unique user interfaces.

Props for Customization: Components can receive data, called “props”, from their parent components. This allows you to customize the behavior and appearance of a component based on the context in which it is used.

State Management: Components can manage their own internal state. This is important for handling dynamic behavior, such as form input, toggling UI elements, and more.

Separation of Concerns: Components promote a separation of concerns between different parts of your application. For example, you can have separate presentation (UI) and logic (container components) components.

Scaling and Collaboration: Components make it easier for multiple developers to work on a project simultaneously. Different developers can focus on different components, and then those components can be integrated into the larger application.

Overall, components play a crucial role in building maintainable, scalable, and organized React applications. They promote code reusability, separation of concerns, and efficient collaboration among developers.

Types of Components

In React, there are two main types of components:

Functional Components:

• Also known as Stateless Functional Components or Functional Stateless Components (FSC).
• They are JavaScript functions that take props as an argument and return React elements.
• Before the introduction of Hooks in React 16.8, functional components couldn’t manage state or lifecycle methods. With Hooks, they gained the ability to manage state and side effects.
• They are simpler and more concise than class components.
• Functional components are recommended for most use cases due to their simplicity and the power of Hooks.

Example:

import React from 'react';

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

Class Components:

• Also known as Stateful Components or Class State Components.
• They are ES6 classes that extend React.Component and can have state, lifecycle methods, and other class features.
• Class components were the original way of creating components in React and are still supported.
• They are useful for more complex components that require state management and lifecycle methods.

Example:

import React, { Component } from 'react';

class MyComponent extends Component {
  constructor(props) {
    super(props);
    this.state = {
      // initial state values
    };
  }

  render() {
    return <div>Hello, {this.props.name}!</div>;
  }
}

Difference between Stateful and Stateless components

Stateful vs Stateless

Tabular Format