Created
June 7, 2019 06:41
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Note React Hooks
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`javascript | |
import React, { forwardRef, useRef, useImperativeHandle } from 'react'; | |
// We need to wrap component in `forwardRef` in order to gain | |
// access to the ref object that is assigned using the `ref` prop. | |
// This ref is passed as the second parameter to the function component. | |
const Child = forwardRef((props, ref) => { | |
// The component instance will be extended | |
// with whatever you return from the callback passed | |
// as the second argument | |
useImperativeHandle(ref, () => ({ | |
getAlert() { | |
alert("getAlert from Child"); | |
} | |
})); | |
return <h1>Hi</h1>; | |
}); | |
const Parent = () => { | |
// In order to gain access to the child component instance, | |
// you need to assign it to a `ref`, so we call `useRef()` to get one | |
const childRef = useRef(); | |
return ( | |
<div> | |
<Child ref={childRef} /> | |
<button onClick={() => childRef.current.getAlert()}>Click</button> | |
</div> | |
); | |
}; | |
` |
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