51 lines
1.4 KiB
Markdown
51 lines
1.4 KiB
Markdown
---
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title: ControlledInput
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tags: components,state,effect,intermediate
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---
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Renders an `<input>` element with internal state, that uses a callback function to pass its value to the parent component.
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- Use object destructuring to set defaults for certain attributes of the `<input>` element.
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- Use the `React.setState()` hook to create the `value` state variable and give it a value of equal to the `defaultValue` prop.
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- Use the `React.useEffect()` hook with a second parameter set to the `value` state variable to call the `callback` function every time `value` is updated.
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- Render an `<input>` element with the appropriate attributes and use the the `onChange` event to upda the `value` state variable.
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```jsx
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function ControlledInput({
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callback,
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type = 'text',
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disabled = false,
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readOnly = false,
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defaultValue,
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placeholder = ''
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}) {
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const [value, setValue] = React.useState(defaultValue);
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React.useEffect(() => {
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callback(value);
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}, [value]);
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return (
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<input
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defaultValue={defaultValue}
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type={type}
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disabled={disabled}
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readOnly={readOnly}
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placeholder={placeholder}
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onChange={({ target: { value } }) => setValue(value)}
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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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<ControlledInput
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type="text"
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placeholder="Insert some text here..."
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callback={val => console.log(val)}
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/>,
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document.getElementById('root')
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);
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```
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