React Essentials · Components & JSX · Lesson 1 of 26
What is a Component?
Concept
What is a Component?
A component is a reusable, self-contained piece of UI written as a function that returns JSX.
By the end of this lesson
- Explain the core idea behind What is a Component?.
- Predict output before running a change.
- Test one realistic and one unusual input.
- Use the result to make the next decision.
How to study this page
- 1. Read one concept.
- 2. Change the example.
- 3. Run, compare, and explain.
- 4. Complete the challenge below.
Self-check before continuing
Without looking at the example, describe what changes when you modify one input in What is a Component?. Then reopen the editor and prove your explanation with a small test.
You are ready to continue when you can predict, test, and explain the result.
Your turn
Write a component called Greeting that renders your name in an h2.
Need a nudge?
Ask about this lesson or your next move. The guide explains the path without taking the work away from you.
Ready for the next lesson?
Mark this lesson complete when you have finished the exercise.
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