Function shouldUpdate

compat/src/memo.js:12–21

(nextProps)

 */
export function memo(c, comparer) {
	function shouldUpdate(nextProps) {
		let ref = this.props.ref;
		if (ref != nextProps.ref && ref) {
			typeof ref == 'function' ? ref(null) : (ref.current = null);
		}

		return comparer
			? !comparer(this.props, nextProps) || ref != nextProps.ref
			: shallowDiffers(this.props, nextProps);
	}

	function Memoed(props) {
		this.shouldComponentUpdate = shouldUpdate;