https://callfrosty.com/wp-content/themes/hypercore/assets/js/scroll-fade.js?ver=1.4.12

1(function (d) {
2
3  const fade = d.querySelectorAll('.lnb-fade');
4
5  // Create Intersection Observer
6  let options = {
7    root: null, //viewport
8    rootMargin: "0px",
9    threshold: .75
10  };
11
12  let o = new IntersectionObserver(([fade]) => {
13
14    if (fade.isIntersecting) {
15
16      fade.target.classList.add('active');
17
18    }
19  }, options);
20
21
22  // Test if element is already in viewport
23  function isInViewport(elem) {
24    const rect = elem.getBoundingClientRect();
25    return (
26      rect.top >= 0 &&
27      rect.left >= 0 &&
28      rect.bottom <= (window.innerHeight || d.documentElement.clientHeight) &&
29      rect.right <= (window.innerWidth || d.documentElement.clientWidth)
30    );
31  }
32
33
34  // Allow data attributes to customize transition duration & delay
35  function setDataAttributes(elem) {
36
37    let duration = elem.getAttribute('data-duration');
38    let delay = elem.getAttribute('data-delay');
39
40    if (duration !== null) {
41      elem.style.transitionDuration = duration + 's';
42    }
43
44    if (delay !== null) {
45      elem.style.transitionDelay = delay + 's';
46    }
47
48  }
49
50
51  // Set observers
52  if (fade.length !== 0) {
53  
54    fade.forEach(fade => {
55
56      o.observe(fade);
57
58      // make element visible if in viewport
59      if (isInViewport(fade)) {
60        fade.classList.add('active');
61      }
62
63      // set transition duration & delay (if applicable)
64      for (let child of fade.children) {
65        setDataAttributes(child);
66      }
67
68    });
69  }  
70})(document);