https://www.german-design-award.com/_assets/a97846525f777edc006e67fd1a4c80c1/JavaScript/object-fit.js

1/*! Created by: Udo Schmal | https://www.gocher.me/ */
2(function() {
3  'use strict';
4  if ('objectFit' in document.documentElement.style === false) {
5    console.log('object-fit fix');
6    function cover(el) {
7      var bounding = el.parentNode.getBoundingClientRect(), height, width, src;
8      if (el.tagName.toLowerCase() == 'img') {
9        width = el.naturalWidth;
10        height = el.naturalHeight;
11        src = el.src;
12      } else if (el.tagName.toLowerCase() == 'video') {
13        width = el.videoWidth; 
14        height = el.videoHeight;
15        src = el.getElementsByTagName("source")[0].src;
16      }
17      console.log('use object-fit.js for ' + src);
18      if ((bounding.width != 0) && (bounding.height != 0)) {
19        if ((bounding.width / bounding.height) > (width / height)) {
20          el.style.height = 'auto';
21        } else {
22          el.style.width = 'auto';
23        }
24      }
25    }
26    var els = document.querySelectorAll('.fit-cover'), len = els.length, i;
27    for (i=0; i < len; i++) {
28      if (els[i].tagName.toLowerCase() == 'img') {
29        if (!els[i].complete || (els[i].naturalWidth === 0)) {
30          els[i].addEventListener("load", function (event) { cover(this); });
31        } else {
32          cover(els[i]);
33        }
34      } else if (els[i].tagName.toLowerCase() == 'video') {
35        if (els[i].videoWidth == 0) {
36          els[i].addEventListener("loadedmetadata", function (event) { cover(this); });
37        } else {
38          cover(els[i]);
39        }
40      }
41    }
42  } else {
43    console.log('native object-fit');
44  }
45})();