function getNeededColumns( selector, width = window.innerWidth ) {
	const minWidths = getCachedMinWidths();
	const minWidthItems = minWidths.get( selector );
	if ( !minWidthItems ) {
		throw new Error( `Can't calculate needed columns, invalid selector: ${selector}` );
	}

	return minWidthItems
		.reduce( ( current, next ) => width < next.minWidth ? current : next )
		.numItems;
}
@param {string} selector
@param {number?} width
@return {number}