https://www.fhcm.paris/modules/custom/fhcm_house/js/list-effects.js?v=1

1(function($) {
2  Drupal.behaviors.houseListEffects = {
3    attach: function (context, settings) {
4      once('houseListEffects', '.house-list', context).forEach((el, idx) => {
5        const isSmall = window.matchMedia('(max-width: 768px)').matches
6        const elements = document.querySelectorAll(".house")
7        const observer = new IntersectionObserver(entries => {
8          entries.forEach(entry => {
9            if(entry.isIntersecting) {
10              entry.target.classList.remove('offscreen')
11              observer.unobserve(entry.target)
12
13              if(isSmall) {
14                el = $(entry.target)
15                el.prepend('<div class="img"><img src="' + el.data('img') + '"/></div>')
16              }
17            }
18          })
19        }, {
20          threshold: .9
21        })
22
23        elements.forEach(element => {
24          if(!isSmall) {
25            const rand = (0.2 + Math.random() * 0.4)  + 's'
26            element.style.transitionDelay = rand
27          }
28          observer.observe(element)
29        })
30      })
31    }
32  }
33
34})(jQuery);