React onBlur回调中使用document.activeElement返回body完美解决方案

export default function Cart() {
	const [isCartOpen, setIsCartOpen] = useState(false)
	
	function clickHandler() {
		setIsCartOpen(!isCartOpen)
	}

	function closeCartDropdown() {
            if(!document.querySelector('#cart').contains(document.activeElement)) {
                    setIsCartOpen(false)
            }
	}

	return (
		<div id="cart" className="relative" onBlur={closeCartDropdown}>
			<div tabIndex={0} onClick={clickHandler} className='relative hover:-translate-y-0.5 active:translate-y-0 transition-transform cursor-pointer'>
				<img className='h-14' src="/src/assets/images/shopping_bag.png" alt="shopping bag" />
				<span className='Z-10 text-2xl font-bold absolute left-1/2 -translate-x-1/2 -translate-y-2/3' style={{top:'70%'}}>4</span>
			</div>
			{
				<CartDropdown isCartOpen={isCartOpen}/>
			}
		</div>
	)
}

function closeCartDropdown() {
	setTimeout(() => {
             if(!document.querySelector('#cart').contains(document.activeElement)) {
		setIsCartOpen(false)
             }
        }, 0)
}