Sniff for user scroll position, fire things once section enters screen

HomeController.js

var HomeController = (function(){


		var
			sections,
			sectionsArray,
			scrollTicking = false,
			scrollAnimationClass = "pre_animate",
			latestKnownScrollY
		;

		var sectionScroll;

		var init = function(){
			sections = document.querySelectorAll('.refresh-section');
			sectionsArray = Array.prototype.slice.call(sections);

			sectionScroll = sectionsArray.map(function(){
				this.fired = false;
				return {
					fired: false
				}
			});

			//push loaded class to video once it "can play through"
				var mainVid;
		        if(window.innerWidth >= 700){
		            $('#mobileVid').remove();
					mainVid = document.getElementById('desktopVid');
		        } else{
					$('#desktopVid').remove();
					mainVid = document.getElementById('mobileVid');
		        }

				mainVid.addEventListener('loadeddata', videoReady);
				mainVid.load();

				function videoReady(){
					mainVid.classList.add('loaded');
					Listeners();
					mainVid.removeEventListener('loadeddata', videoReady);
				}

				HomeModal.deeplink();

				IEfix();
		}

		function IEfix(){
			if(navigator.userAgent.indexOf('Trident') > -1 || navigator.userAgent.indexOf('Edge') > -1){
				$('.blob').remove();
			}
		}

		var Listeners = function(){
			TagListener();
			scrollListener();
			window.addEventListener("scroll", scrollListener);

			if (window.innerWidth < 700){
				window.addEventListener("scroll", ctaScrollListener);
			}
		};

		var ctaScrollListener = function(){
			if (window.pageYOffset > (sections[1].offsetTop - window.innerHeight/2)){
				$('#mobile-fixed-ctas').addClass('in_view');
			} else {
				$('#mobile-fixed-ctas').removeClass('in_view');
			}
		}

		function scrollListener() {
			latestKnownScrollY = window.pageYOffset;
			requestScrollTick();
		}

		function requestScrollTick() {

			if(!scrollTicking) {
				requestAnimationFrame(scrollAnimateHandler);
			}
			scrollTicking = true;
		}


		var currentScrollY;
		var scrollTimer;

		var scrollAnimateHandler = function(){

			scrollTicking = false;

			currentScrollY = latestKnownScrollY;

			for ( var s = 0; s < sections.length; s++){
				if (currentScrollY > sections[s].offsetTop - window.innerHeight/2 && sectionScroll[s].fired == false){
					sectionScroll[s].fired = true;
					sections[s].classList.remove(scrollAnimationClass);

					var dataFunction = sections[s].getAttribute('data-function');
					var tagSection = sections[s].getAttribute('id').replace('_','');

					if (dataFunction !== undefined){
						window[dataFunction]();
					}
				}


				if (sections[s].getBoundingClientRect().top + sections[s].getBoundingClientRect().height < window.innerHeight/2
				 || sections[s].getBoundingClientRect().top > window.innerHeight/2){
					 sections[s].classList.remove('t_pv');
				} else {
					if( $(sections[s]).hasClass('t_pv') == false ) {
						var tagSection = sections[s].getAttribute('id').replace('_','');
						viewHandler(tagSection);
						sections[s].classList.add('t_pv');
						// setTimeout(function(){
						// 	whichVidsPaused();
						// }, 50);
					}
				}


				if (sections[s].getBoundingClientRect().top + sections[s].getBoundingClientRect().height < 0
				 || sections[s].getBoundingClientRect().top > window.innerHeight){
						sections[s].classList.add('o_s'); //o_s = off screen
						if(sectionsArray[s].querySelector('video')){
							sectionsArray[s].querySelector('video').pause();
						}
				} else {
					if ( $(sections[s]).hasClass('o_s') ) {
						sections[s].classList.remove('o_s');
						var tagSection = sections[s].getAttribute('id').replace('_','');

						if(sectionsArray[s].querySelector('video')){
							sectionsArray[s].querySelector('video').play();
						}
					}
				}
			}

		};

		return {
			init: init,
			scrollAnimateHandler: scrollAnimateHandler,
			ctaScrollListener: ctaScrollListener
		}
})();



// output which video is paused, which aren't
function whichVidsPaused(){
	vids = document.querySelectorAll('video');
	for(v = 0; v < vids.length; v++){
		console.log(vids[v].getAttribute('id') + ' is paused: ' + vids[v].paused);
	}
}