REACT MASTER CLASS /// UI COMPONENTS /// WRITE JSX /// MODULAR ARCHITECTURE /// REACT MASTER CLASS /// UI COMPONENTS /// WRITE JSX /// MODULAR ARCHITECTURE ///

React Components

Learn how to build reusable UI elements. Master functional components, JSX syntax, and module exports.

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Tutor:React applications are built from isolated pieces of UI called 'Components'. A component is essentially a JavaScript function that returns markup.


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UNLOCK NODES BY MASTERING COMPONENTS.

Concept: Functions

A React component is a JavaScript function that returns markup. Its name must be capitalized.

System Check

Which of the following is a valid React Component declaration?

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React Components & JSX

Author

Pascual Vila

Frontend Instructor // Code Syllabus

Components are the core building block of React. A component is a piece of the UI (user interface) that has its own logic and appearance. Think of them like custom HTML elements.

Functional Components

In modern React, components are written as JavaScript functions. A functional component is simply a JavaScript function that returns React elements (JSX). To make it a valid component, the function name must start with a capital letter.

What is JSX?

JSX stands for JavaScript XML. It allows us to write HTML directly inside JavaScript. Under the hood, React transforms this JSX into standard JavaScript code that manipulates the DOM. Remember that you can only return one parent element from a component.

Nesting and Exporting

Components can be nested inside other components, exactly like HTML tags. To use a component created in one file inside another file, you use the ES6 Modules syntax: export default ComponentName; and then import it where needed.

View Full Transcript+

This section contains the full detailed transcript of the React Components Creation lesson. It deeply covers the shift from Class Components to Functional Components, the rules of JSX (camelCase attributes, closing all tags), and how React builds a Virtual DOM based on these component trees.

React Glossary

Component

An independent, reusable piece of the UI. In modern React, they are JavaScript functions that return JSX.

snippet.jsx

JSX

A syntax extension for JavaScript that looks similar to XML or HTML. It describes what the UI should look like.

snippet.jsx

PascalCase

A naming convention where the first letter of each word is capitalized. React requires this for user-defined components.

snippet.jsx

Fragment (<> </>)

A pattern in React for a component to return multiple elements without adding extra nodes to the DOM.

snippet.jsx

export default

ES6 syntax used to export a single class, function or primitive from a script file.

snippet.jsx

Self-closing Tag

In JSX, elements without children must be explicitly closed with a trailing slash.

snippet.jsx