function_menuHighlight.js

$(function(){
	//console.info('menu menuHighlight running');
	let menuElement = $('.mc-menu')
		, allElements = $('.mc-menu__top__logo, .mc-menu__top__menu-button')
		, anchorMap = [];

	$('.mc-menu__top__logo, .mc-menu__top__menu-button').each(function(){
		anchorMap.push( $( $(this).attr('href') ) );
	});

	//first run
	menuHighlight(menuElement, anchorMap, allElements);
	setTimeout(function(){
		menuHighlight(menuElement, anchorMap, allElements);
	}, 250);

	//events to run
	$(window).on('scroll', function(){
		//console.info('scroll');
		menuHighlight(menuElement, anchorMap, allElements);
		setTimeout(function(){
			menuHighlight(menuElement, anchorMap, allElements);
		}, 250);
	});
	$(window).on('resize', function(){
		//console.info('resize');
		menuHighlight(menuElement, anchorMap, allElements);
		setTimeout(function(){
			menuHighlight(menuElement, anchorMap, allElements);
		}, 250);
	});

	function menuHighlight(menuElement, anchorMap, allElements){
		let scrollYNow = scrollY
			, getPositions = []
			, menuHeight = menuElement.innerHeight()
			, windowHeight = $(window).innerHeight / 4
			, active = false;

		anchorMap.forEach(function(item, i){
			getPositions.push({
				'min': item.offset().top,
				'max': typeof anchorMap[i+1] != 'undefined' ? ( anchorMap[i+1].offset().top - 1 ) : 999999
			});
		});

		//fix getPositions
		getPositions.pop();
		getPositions[ getPositions.length - 1 ].max = 999999;

		getPositions.forEach(function(item, i){
			//console.info('scrollYNow: ' + scrollYNow, 'item.min: ' + item.min, 'item.max: ' + item.max, 'i: ' + i );
			if( scrollYNow >= item.min - menuHeight - 40 && scrollYNow <= item.max - menuHeight - 40 && !active ){
				allElements.removeClass('active');
				allElements.eq(i).addClass('active');
				setTimeout(function(){
					allElements.eq(i).addClass('active');
				});
				active = true;
			};
		});
		if( active == false ){
			allElements.removeClass('active');
			anchorMap[ anchorMap.length - 1 ].addClass('active');
				anchorMap[ anchorMap.length - 1 ].addClass('active');
		};
		return false;
	};

});