Expert-Level Explanation

React elements are the fundamental building blocks of React applications. They are objects that represent a part of the UI. React elements are immutable, meaning that once they are created, their children and attributes cannot be changed. This immutability helps in efficient updating and rendering of the UI. An element describes what you want to see on the screen. It is not a component but rather an object representation of some UI. Elements are what components return, and they tell React what to render. Essentially, elements are lightweight descriptions of what should appear on the screen.

Creative Explanation

Think of React elements as blueprints in architecture. Just as a blueprint defines the structure of a building without being the actual building, React elements define the structure of the UI without being the actual elements on the screen. They are plans or instructions that React follows to construct the DOM. This approach allows React to work efficiently, updating the UI in the most optimal way, much like how an architect updates a building plan without rebuilding the entire structure.

Practical Explanation with Code

Here's a simple example of creating a React element:

import React from 'react';

const element = <h1>Hello, world!</h1>;

export default element;

In this example, the variable element is a React element. It tells React to render an <h1> tag with the text "Hello, world!" to the DOM.

Real-World Example

In a real-world application, such as a news website, each news article, headline, and image could be represented as React elements. These elements are managed by React to render the content on the page. When a new article is loaded, React only updates the necessary elements, such as the text and images, without reloading the entire page.