https://grueneliga.de/media/plg_system_imagesizer/js/groups.js?cd425d

1
2(function (window, document) {
3    'use strict';
4
5    var ImageSizer = window.ImageSizer = window.ImageSizer || {};
6
7    ImageSizer.ready = function (fn) {
8        if (document.readyState === 'loading') {
9            document.addEventListener('DOMContentLoaded', fn);
10        } else {
11            fn();
12        }
13    };
14
15    ImageSizer.containerOf = function (link) {
16        return link.closest('.gallery') || link.closest('div, p') || document.body;
17    };
18
19    ImageSizer.groups = function (selector, fn) {
20        var containers = [];
21        var members = [];
22
23        Array.prototype.forEach.call(document.querySelectorAll(selector), function (link) {
24            var container = ImageSizer.containerOf(link);
25            var index = containers.indexOf(container);
26
27            if (index < 0) {
28                index = containers.push(container) - 1;
29                members.push([]);
30            }
31
32            members[index].push(link);
33        });
34
35        containers.forEach(function (container, index) {
36            fn(container, index, members[index]);
37        });
38
39        return containers;
40    };
41
42    ImageSizer.ensureAttr = function (el, attr, fallback) {
43        if (!el.hasAttribute(attr)) {
44            var value = el.getAttribute('data-gallery') || fallback || '';
45
46            if (value !== '') {
47                el.setAttribute(attr, value);
48            }
49        }
50    };
51})(window, document);