React Essentials · Hooks · Lesson 8 of 26
useState Recap
Concept
useState Recap
useState is the most common hook. It stores a value and a function used to update it.
By the end of this lesson
- Explain the core idea behind useState Recap.
- 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 useState Recap. 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
Use useState to track whether a sidebar is open or closed.
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Console