<html lang="ko">
<body>
<div id="root"></div>
</body>
<script src="https://unpkg.com/react@17/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
<script type="text/babel">
const root = document.querySelector("#root");
function App() {
const [amount, setAmount] = React.useState("");
const [inverted, setInverted] = React.useState(false);
const onChange = (event) => {
setAmount(event.target.value);
};
const reset = () => setAmount(0)
const onInvert = () => {
setInverted((current) => !current);};
return (
<div>
<h1>converter</h1>
<div>
<label htmlfor="minutes">Minutes</label>
<input
value={inverted ? amount * 60 : amount}
id="minutes"
placeholder="Minutes"
type="number"
onChange={onChange}
disabled={inverted}
/>
</div>
<div>
<label htmlfor="hours">Hours</label>
<input
value={inverted ? amount : Math.round(amount / 60)}
id="hours"
placeholder="Hours"
type="number"
disabled={!inverted}
/>
</div>
<button onClick={reset}>Reset</button>
<button onClick={onInvert}>{inverted ? "Turn back" : "Invert"}</button>
</div>
);
}
ReactDOM.render(<App />, root);
</script>
</html>input의 disabled 속성은 인풋을 비활성화 시킨다.
input 값은controlled component로 만들자.
setState()에 함수를 할당하는 것을 잘 활용하면 이전 state를 손쉽게 바꿀 수 있다.
안녕하세요.