useRef
/*
A common use case is to access a child imperatively:
*/
function TextInputWithFocusButton() {
const inputEl = useRef(null);
const onButtonClick = () => {
// `current` points to the mounted text input element
inputEl.current.focus();
};
return (
<>
<input ref={inputEl} type="text" />
<button onClick={onButtonClick}>Focus the input</button>
</>
);
}react callback
import React, {useState} from 'react';
// Create a callback in the probs, in this case we call it 'callback'
function newCallback(callback) {
callback('This can be any value you want to return')
}
const Callback = () => {
const [callbackData, setCallbackData] = useState('')
// Do something with callback (in this case, we display it on screen)
function actionAferCallback (callback) {
setCallbackData(callback)
}
// Function that asks for a callback from the newCallback function, then parses the value to actionAferCallback
function requestCallback() {
newCallback(actionAferCallback)
}
return(
<div>
{/* A button to activate callback */}
<button onClick={() => {requestCallback()}}>Request Callback</button>
{callbackData}
</div>
)
}
export default Callback;Copyright © 2021 Codeinu
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