In React, components are the fundamental building blocks of a user interface. They enable developers to create independent, reusable pieces of the user interface that can be combined to form more significant UI elements.

You can think of a React app as a tree of components, with the top-level component as the root. Each component is responsible for rendering JSX markup, defining the desired HTML structure displayed in the Browser DOM.

Functional Components

Functional components are JavaScript functions that return JSX to define the structure and content of a UI element. They represent the modern way to build React apps and are named with capitalized letters, such as Product or User, to differentiate them from standard HTML elements like div or span.

Functional components offer several advantages:

• Less Boilerplate: Functional components reduce boilerplate code, making them more concise and easier to work with;
• Easier to Perceive: They are easier to understand and perceive, especially for developers new to React;
• Easier to Test: Functional components facilitate testing due to their straightforward nature;
• No Context (this): Unlike class components, functional components don't involve context (this), simplifying your code. Here's an example of a functional component:

const Product = () => (
  <div>
    <h2>HolaFood</h2>
    <p>Price: $19.99</p>
    <button type="button">Add to Cart</button>
  </div>
);

In this example, Product is a functional component representing a product card.

Functional components make up the majority of a React app's structure, serving as the essential building blocks for creating user interfaces.