function MeasureExample() {
const [rect, ref] = useClientRect();
return (
Hello, world
{rect !== null &&
The above header is {Math.round(rect.width)}px wide
}
);}function useClientRect() {
const [rect, setRect] = React.useState(null);
const ref = React.useCallback(node => {
if (node !== null) {
setRect(node.getBoundingClientRect());
}
}, []);
return [rect, ref];}