JSX, Rendering, Expressions, and Component Templates
Learn how JSX works, why it looks like HTML but behaves like JavaScript, and how React turns component code into rendered UI.
Inside this chapter
- What JSX Is
- Embedding Expressions
- JSX Rules Beginners Must Learn
- Why JSX Is Useful
- Practical Example
Series navigation
Study the chapters in order for the clearest path from React fundamentals to advanced architecture, optimization, testing, and product-ready frontend engineering. Use the navigation at the bottom to move smoothly through the full tutorial series.
What JSX Is
JSX is a syntax extension that lets developers write UI structure inside JavaScript. It resembles HTML, but it is not raw HTML. JSX is converted during build time into JavaScript function calls that describe the interface tree.
Embedding Expressions
function WelcomeCard() {
const student = 'Riya';
return <h2>Hello, {student}</h2>;
}Curly braces allow JavaScript expressions inside JSX. This is how components display dynamic values, computed labels, mapped collections, and conditional content.
JSX Rules Beginners Must Learn
- Components must return one parent element or a fragment
- Use
classNameinstead ofclass - JavaScript expressions go inside curly braces
- Self-closing tags such as
<img />must be closed properly
Why JSX Is Useful
JSX keeps structure and UI logic close together. That makes components easier to understand because the rendered output and the data that drives it live in one place. Critics sometimes dislike mixing markup and logic, but in practice this model works very well for dynamic interfaces.
Practical Example
A product card component might show the name, price, stock state, badge, and button label based on data. JSX lets all those rendering decisions live together instead of being split across multiple disconnected templating systems.