Ciro Santilli
OurBigBook.comreact/context.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Context</title>
<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@7.14.7/babel.min.js"></script>
</head>
<body>
<div id="root"></div>
<script type="text/babel">
const CounterContext = React.createContext();
function Main(props) {
console.log('Main');
const [n, setN] = React.useState(0)
function handleClick() {
console.log('handleClick');
setN(n + 1)
}
return (
<div>
<div onClick={handleClick}>Click me</div>
<div>{n}</div>
<CounterContext.Provider value={{n, handleClick}}>
<Child />
</CounterContext.Provider>
</div>
)
}
function Child(props) {
console.log('Child');
return (<Child2 />)
}
function Child2(props) {
console.log('Child2');
const {n, handleClick} = React.useContext(CounterContext);
return (
<>
<div>Child2</div>
<div onClick={handleClick}>Click me 2</div>
<div>{n}</div>
</>
)
}
ReactDOM.render(
<Main />,
document.getElementById('root')
);
</script>
</body>
</html>