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codstak / counter-cardReact challenge
React15–20 min
Challenge 01
Counter card
Practice state-driven rendering by building a counter with increment, decrement, and reset actions.
Create the count state
Connect all three actions
Keep the output accessible
App.tsxstyles.css
import { useState } from "react";
export default function Counter() {
const [count, setCount] = useState(0);
return (
<section className="counter">
<output>{count}</output>
<button onClick={() => setCount(count + 1)}>
Increase
</button>
</section>
);
}
Live preview
React state
1
AI coach
Your increment works. Now try using the callback form of the state setter so rapid updates always use the latest value.
setCount(value => value + 1)
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Why does my state update show the old value?
React schedules state updates. Instead of reading the value immediately after setting it, derive what you need during render—or use the callback form when the next value depends on the previous one.
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