https://playthebazaar.com/js/intersectionObserver.js?v=1.1

1window.createIntersectionObserver = function (elementRef, className, thresholdValue) {
2    const options = {
3        threshold: thresholdValue
4    }
5    const observer = new IntersectionObserver(entries => {
6        entries
7            .forEach(entry => {
8                if (entry.isIntersecting) {
9                    entry.target.classList.add(className);
10                    observer.unobserve(entry.target);
11                }
12                
13            });
14    }, options);
15    observer.observe(elementRef);
16}
17
18window.createParallaxObserver = function (elementRef, thresholdValue) {
19    const options = {
20        threshold: thresholdValue
21    }
22
23    function handleScroll() {
24        const currentVW = window.innerWidth;
25        const maxOffset = currentVW > 500 ? -elementRef.offsetParent.offsetTop * 0.4 : -elementRef.offsetParent.offsetTop * 0.2;
26        const minOffset = 0;
27        const scrollOffset = currentVW > 500 ? -window.scrollY * 0.9 : -window.scrollY * 1.2;
28        let offset = Math.max(scrollOffset + 200, maxOffset);
29        offset = Math.min(offset, minOffset);
30        elementRef.style.transform = `translateY(${offset}px)`;
31    }
32
33    const observer = new IntersectionObserver(entries => {
34        entries
35            .forEach(entry => {
36                if (entry.isIntersecting) {
37                    document.addEventListener("scroll", handleScroll);
38                } else {
39                    document.removeEventListener("scroll", handleScroll);
40                }
41
42            });
43    }, options);
44    observer.observe(elementRef);
45}