1. Introduction

Goal of this Tutorial

This tutorial aims to provide a comprehensive understanding of how to build and use React Components - the building blocks of any React application. By the end of this tutorial, you should be able to create reusable components and integrate them into your application.

What You Will Learn

• What React components are
• The difference between class components and functional components
• How to create and use React components
• How to pass data through props
• How to manage state in a component

Prerequisites

• Basic understanding of JavaScript and how to use it to manipulate the DOM.
• Familiarity with ES6+ syntax (let/const, arrow functions, destructuring).
• Basic understanding of HTML and CSS.

2. Step-by-Step Guide

Understanding React Components

Components are independent, reusable pieces of code. They serve the same purpose as JavaScript functions but work in isolation and return HTML via a render function.

There are two types of components in React: functional components and class components. Functional components are just JavaScript functions. They accept properties (props) as an argument and return a React element. On the other hand, class components are ES6 classes that extend the Component class from React library.

Creating a Simple React Component

A React component can be created using a JavaScript function or a class. Here's a simple example of a functional component:

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

And here's how you can create the same component, but as a class:

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

Using a React Component

React components can be used just like regular JSX tags. They can be self-closing or can wrap other content:

<Welcome name="Sara" />

3. Code Examples

Greeting Component

Let's create a 'Greeting' component which will display a greeting message based on the time of day.

function Greeting(props) {
  const date = new Date();
  const hours = date.getHours();
  let timeOfDay;

  if (hours < 12) {
    timeOfDay = "morning";
  } else if (hours >= 12 && hours < 17) {
    timeOfDay = "afternoon";
  } else {
    timeOfDay = "night";
  }

  return <h1>Good {timeOfDay}, {props.name}!</h1>;
}

You can use this component in the following way:

<Greeting name="John" />

4. Summary

In this tutorial, we've learned about React components, how they are created, and how they can be used. We've also learned about the difference between functional and class components, and how to pass data through props.

For further learning, you can explore more complex concepts like component lifecycle, hooks, and context API. Refer to the official React documentation for more details.

5. Practice Exercises

1. Create a 'UserProfile' component that displays a user's name, email, and profile picture. The data should be passed in as props.

2. Create a 'Counter' component that increments a count each time a button is clicked. Use state to manage the count.

3. Create a 'TodoList' component. This should include an input field for adding todos, a button to add the todo to the list, and a list displaying all the todos. Use state to manage the todos.

Remember, practice is key when it comes to learning new concepts, so keep building with React!