React Components Explained: A Beginner's Guide

Learn React Components with practical examples. Understand reusable UI, functional components, component composition, project structure, and React best practices.

React Components Explained: The Building Blocks of Every React Application

If JSX is the language used to build React user interfaces, then components are the building blocks that make React powerful.

Almost everything you see in a React application is a component.

Examples include:

• navigation bars
• buttons
• cards
• forms
• sidebars
• footers
• dashboards

Understanding components is one of the most important steps in learning React because every React application is built using them.

In this guide, you'll learn what React components are, why they're important, and how to create reusable components like professional developers.

Prerequisites

Before learning React Components, make sure you understand:

• React.js Introduction
• React Setup and Folder Structure
• JSX in React
• JavaScript Functions

These concepts are used extensively when creating components.

What is a React Component?

A React component is a reusable piece of UI.

Think of components like LEGO blocks.

Instead of building an entire application from one large file, React allows developers to split the UI into smaller reusable pieces.

Example:

  function Welcome() {
  return (
    <h1>
      Welcome to React
    </h1>
  );
}
  

This is a React component.

Why Components Matter

Imagine building a website with:

• Navbar
• Sidebar
• Footer
• Hero Section
• Product Cards

Without components, you would repeatedly write the same code.

With React:

  <Navbar />
<Hero />
<ProductCard />
<Footer />
  

Each part becomes reusable.

Benefits include:

• cleaner code
• easier maintenance
• better scalability
• improved readability

Components in Real Applications

A typical application may look like:

  App

├── Navbar
├── Hero
├── Features
├── Testimonials
├── Footer
  

Every section is a separate component.

This approach makes large applications easier to manage.

Creating Your First Component

Example:

  function Header() {
  return (
    <h1>
      My Blog
    </h1>
  );
}

export default Header;
  

This component displays a heading.

Using a Component

Once created, a component can be imported and used.

Example:

  import Header from "./Header";

function App() {
  return (
    <Header />
  );
}
  

React renders the component wherever it is used.

Component Naming Rules

React components must start with an uppercase letter.

Correct:

  function Navbar() {
  return <h1>Navbar</h1>;
}
  

Incorrect:

  function navbar() {
  return <h1>Navbar</h1>;
}
  

React treats lowercase names as HTML elements.

Functional Components

Modern React primarily uses functional components.

Example:

  function Button() {
  return (
    <button>
      Click Me
    </button>
  );
}
  

Functional components are:

• simpler
• easier to read
• widely used in modern React

Returning JSX

Every component returns JSX.

Example:

  function Hero() {
  return (
    <section>

      <h1>
        Learn React
      </h1>

      <p>
        Build modern applications.
      </p>

    </section>
  );
}
  

The returned JSX becomes part of the user interface.

Reusing Components

One of React's biggest strengths is reusability.

Example:

  <ProductCard />

<ProductCard />

<ProductCard />
  

Instead of creating multiple cards manually, one component can be reused many times.

Organizing Components

Professional React projects usually store components inside a dedicated folder.

Example:

  src/

├── components/
│
├── pages/
│
├── assets/
  

Inside components:

  components/

├── Navbar.jsx
├── Footer.jsx
├── Button.jsx
├── Card.jsx
  

This structure keeps projects organized.

Component Composition

React encourages combining smaller components into larger ones.

Example:

  function Layout() {
  return (
    <>
      <Navbar />
      <Hero />
      <Footer />
    </>
  );
}
  

This technique is called component composition.

Real-World Example

A blog card component:

  function BlogCard() {
  return (
    <div className="border p-4">

      <h2>
        React Components
      </h2>

      <p>
        Learn reusable UI design.
      </p>

    </div>
  );
}
  

Usage:

  <BlogCard />
<BlogCard />
<BlogCard />
  

A single component creates multiple UI elements.

Behind the Scenes

When React sees:

  <Header />
  

it internally executes:

  Header();
  

and renders the returned JSX.

This is why React components are simply JavaScript functions.

Components vs Regular Functions

At first glance, components look similar to JavaScript functions.

Example:

  function sum(a, b) {
  return a + b;
}
  

React Component:

  function Header() {
  return (
    <h1>
      Header
    </h1>
  );
}
  

Difference:

• Regular functions return values.
• Components return JSX.

Common Beginner Mistakes

Using Lowercase Component Names

Incorrect:

  <header />
  

React interprets this as an HTML element.

Always use uppercase component names.

Keeping Everything in App.jsx

Many beginners place the entire application inside one file.

Instead, split the UI into reusable components.

Creating Huge Components

Large components become difficult to maintain.

Break complex UIs into smaller pieces.

Duplicating UI

If you write the same UI multiple times, consider creating a component.

Watch Full React Components Tutorial

If you prefer video learning, watch the complete tutorial below where we build reusable React components and organize a real-world application.

Watch the Full React Components Tutorial

This tutorial demonstrates how components improve scalability and maintainability.

React vs Next.js

React provides the component system.

Next.js builds on top of React and uses components extensively for pages, layouts, and reusable UI sections.

Learning components is essential before moving to Next.js.

Build Something

Practice components by creating:

• Navigation Bar
• Footer
• Product Card
• User Profile Card
• Blog Card
• Pricing Card

Building reusable UI components is one of the fastest ways to improve React skills.

Production Tip

Professional React developers usually:

• create small reusable components
• keep components focused on one responsibility
• organize components logically
• avoid duplication
• compose larger UIs from smaller pieces

Well-designed components make applications easier to scale.

Why Components Matter

Components help developers:

• write less code
• reuse UI elements
• improve maintainability
• build scalable applications
• create consistent user interfaces

They are the foundation of React development.

Conclusion

React Components are reusable building blocks that allow developers to create modern user interfaces efficiently.

By splitting applications into smaller, manageable pieces, components improve code organization, maintainability, and scalability.

Mastering components is a critical step toward building professional React and Next.js applications.