44 lines
1.1 KiB
Markdown
44 lines
1.1 KiB
Markdown
### Ticker
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Renders a ticker component.
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* Use the `React.useState()` hook to initialize the `ticker` state variable to `0`.
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* Define two methods, `tick` and `reset`, that will periodically increment `timer` based on `interval` and reset `interval` respectively.
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* Return a `<div>` with two `<button>` elements, each of which calls `tick` and `reset` respectively.
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```jsx
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function Ticker(props) {
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const [ticker, setTicker] = React.useState(0);
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let interval = null;
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const tick = () => {
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reset();
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interval = setInterval(() => {
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if (ticker < props.times) setTicker(ticker + 1);
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else clearInterval(interval);
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}, props.interval);
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};
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const reset = () => {
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setTicker(0);
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clearInterval(interval);
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};
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return (
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<div>
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<span style={{ fontSize: 100 }}>{ticker}</span>
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<button onClick={tick}>Tick!</button>
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<button onClick={reset}>Reset</button>
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</div>
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);
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}
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```
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```jsx
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ReactDOM.render(<Ticker times={5} interval={1000} />, document.getElementById('root'));
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```
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<!-- tags: visual,state -->
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<!-- expertise: 1 -->
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