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<div id="root"></div>
body {
height: 100vh;
margin: 0;
display: flex;
justify-content: center;
align-items: center;
}
.box {
width: 250px;
h1 {
font-size: 20px;
margin: 0 0 1rem 0;
}
}
import React, { useState, useRef, useMemo, useEffect } from "https://esm.sh/react@18";
import ReactDOM from "https://esm.sh/react-dom@18";
import _ from 'https://cdn.jsdelivr.net/npm/lodash@4.17.21/+esm'
// * useDebounce hook
const useDebounce = (callback) => {
// 변할 수 있는 훅 ref를 선언한다.
const ref = useRef();
// 상태가 변하여 함수가 변한다면 ref를 갱신한다.
// ref에 들어간 값이 변하더라도 re-rendering이 되지 않는다.
// 따라서 debounce 또는 throttle이 re-rendering 되지 않는다.
useEffect(() => {
ref.current = callback;
}, [callback]);
// debounce 함수를 useMemo 훅에 빈배열의 의존성을 할당해 마운트 될 때 한 번 생성한다.
const debouncedCallback = useMemo(() => {
// func 함수는 마운트 될 때 한 번 생성한다.
const func = () => {
// ref는 변할 수 있다. mutable하다.
// 위의 useEffect로 인하여 ref.current는 최신의 함수를 바라본다.
ref.current?.();
};
// debounce 함수는 마운트 될 때 한 번 생성된다.
// 하지만 최신의 ref.current 값을 상대 참조하고 있다.
return _.debounce(func, 2000);
// useMemo의 의존성은 없다. 마운트 될 때 한 번만 생성된다.
}, []);
return debouncedCallback;
};
// * App
const App = () => {
// button
const sendRequest = () => {
console.log(`✅ Send request`)
}
const onClick = useDebounce(() => sendRequest())
// input
const [value, setValue] = useState('');
const sendRequestWithState = useDebounce(() => {
// send request to the backend
// access to latest state here
console.log(`✅ Send naive request with: ${value}`);
});
const onChange = (e) => {
const value = e.target.value;
setValue(value);
sendRequestWithState();
}
return(
<div>
<div className="box">
<h1>Let's check console.log</h1>
<button
onClick={onClick}
className="button">
Send Backend button!
</button>
</div>
<div className="box">
<h1>Input Text </h1>
<input onChange={onChange} value={value} />
</div>
</div>
);
}
ReactDOM.render(<App />,
document.getElementById("root"))
Also see: Tab Triggers