45 lines
1.1 KiB
Markdown
45 lines
1.1 KiB
Markdown
---
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title: LimitedTextarea
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tags: components,state,callback,event,beginner
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---
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Renders a textarea component with a character limit.
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- Use the `useState()` hook to create the `content` state variable and set its value to that of `value` prop, trimmed down to `limit` characters.
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- Create a method `setFormattedContent`, which trims the content down to `limit` characters and memoize it, using the `useCallback()` hook.
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- Bind the `onChange` event of the `<textarea>` to call `setFormattedContent` with the value of the fired event.
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```jsx
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const LimitedTextarea = ({ rows, cols, value, limit }) => {
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const [content, setContent] = React.useState(value.slice(0, limit));
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const setFormattedContent = React.useCallback(
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text => {
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setContent(text.slice(0, limit));
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},
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[limit, setContent]
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);
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return (
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<>
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<textarea
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rows={rows}
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cols={cols}
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onChange={event => setFormattedContent(event.target.value)}
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value={content}
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/>
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<p>
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{content.length}/{limit}
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</p>
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</>
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);
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};
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```
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```jsx
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ReactDOM.render(
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<LimitedTextarea limit={32} value="Hello!" />,
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document.getElementById('root')
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);
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```
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