getBootstrap4Grid.js

// getBootstrap4Grid.js v1.2.1
function getBootstrap4Grid( windowWidth = window.outerWidth ){
	if( typeof windowWidth == 'string' ){
		windowWidth = +windowWidth;
	};
	if( windowWidth == 1 ){
		windowWidth = window.outerWidth;
		windowWidth = ( windowWidth < 576 ) ? windowWidth = 1 : windowWidth;
		windowWidth = ( windowWidth >= 576 && windowWidth < 768 ) ? windowWidth = 2 : windowWidth;
		windowWidth = ( windowWidth >= 768 && windowWidth < 992 ) ? windowWidth = 3 : windowWidth;
		windowWidth = ( windowWidth >= 992 && windowWidth < 1200 ) ? windowWidth = 4 : windowWidth;
		windowWidth = ( windowWidth >= 1200 ) ? windowWidth = 5 : windowWidth;
		return windowWidth;
	};
	if( typeof windowWidth == 'number' && windowWidth.toString() != 'NaN' ){
		windowWidth = ( windowWidth < 576 ) ? windowWidth = 'xs' : windowWidth;
		windowWidth = ( windowWidth >= 576 && windowWidth < 768 ) ? windowWidth = 'sm' : windowWidth;
		windowWidth = ( windowWidth >= 768 && windowWidth < 992 ) ? windowWidth = 'md' : windowWidth;
		windowWidth = ( windowWidth >= 992 && windowWidth < 1200 ) ? windowWidth = 'lg' : windowWidth;
		windowWidth = ( windowWidth >= 1200 ) ? windowWidth = 'xl' : windowWidth;
		return windowWidth;
	};
	return false;
};

getBootstrap4Grid.min.js

// getBootstrap4Grid.min.js v1.2.1
function getBootstrap4Grid(a=window.outerWidth){return('string'==typeof a&&(a=+a),1==a)?(a=window.outerWidth,a=576>a?a=1:a,a=576<=a&&768>a?a=2:a,a=768<=a&&992>a?a=3:a,a=992<=a&&1200>a?a=4:a,a=1200<=a?a=5:a,a):'number'==typeof a&&'NaN'!=a.toString()&&(a=576>a?a='xs':a,a=576<=a&&768>a?a='sm':a,a=768<=a&&992>a?a='md':a,a=992<=a&&1200>a?a='lg':a,a=1200<=a?a='xl':a,a)}