React

Introduction to React

Posted on Friday, December 16, 2022
Introduction to React

Take your time and see Introduction to React, maybe it is the right programming language for you, it is easy and powerful.

Table Of Contents

React is a popular JavaScript library for building user interfaces. It allows developers to create reusable components that can be easily shared and integrated into other parts of an application.

React follows a declarative programming paradigm, which means that developers describe the desired state of the user interface, and React takes care of rendering the user interface and updating it when the state changes. This makes it easier to reason about and debug an application, as developers do not need to worry about how the user interface is being updated.

Starting a React App

Introduction to React – There are several ways to set up a React app, but the most common way is to use the create-react-app tool. This tool sets up a basic React app with a development server and a build script, so that developers can focus on writing code without worrying about configuration.

To install create-react-app, run the following command:

Copy codenpm install -g create-react-app

This installs the create-react-app command globally, so it can be used from any directory.

To create a new React app, run the following command:

Copy codecreate-react-app my-app

This will create a new directory called my-app with the basic structure of a React app. To start the development server, navigate to the app directory and run the following command:

Copy codecd my-app
npm start

This will start the development server and open the app in a new browser window. The development server automatically reloads the app when any changes are made to the code, so there is no need to manually refresh the page.

Creating a React Component

In React, a component is a piece of code that represents a part of a user interface. Components can be either class-based or function-based.

Here is an example of a simple function-based component in React:

Copy codeimport React from 'react';

function MyComponent(props) {
  return (
    <div>
      <h1>Hello, {props.name}!</h1>
      <p>Welcome to my component.</p>
    </div>
  );
}

This component takes in a single prop called name and renders a heading and a paragraph element. The component is wrapped in a div element, which is a common practice in React to group related elements together.

To use this component in another part of the application, it can be imported and rendered like this:

Copy codeimport React from 'react';
import ReactDOM from 'react-dom';
import MyComponent from './MyComponent';

ReactDOM.render(
  <MyComponent name="John" />,
  document.getElementById('root')
);

This code will render the component inside the element with the id of root in the HTML document.

Using the useState Hook

One of the key concepts in React is state, which refers to the data or variables that determine a component’s behavior. In class-based components, state is typically stored as an object and managed using methods like setState.

In function-based components, state can be managed using the useState hook. The useState hook allows a function-based component to have state, just like a class-based component.

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