https://www.jazel.com/content/plugins/jzl-core/core/lazy-load/js/intersectionObserver.js?ver=20231208-0000

1(function() {
2    "use strict";
3
4    var lazyReadyAttribute = "data-jzl-lazy-ready";
5    var intersectAttribute = "data-jzl-intersect";
6
7    function JazelIntersectionObserver(onLoadHandler) {
8
9        this._io = undefined;
10        this._loadCallback = function() {};
11
12        if (!('IntersectionObserver' in window) || onLoadHandler == null) {
13            this._io = null;
14        } else {
15            var config = {
16                rootMargin: '50px 50px',
17                threshold: 0.01
18            };
19            this._loadCallback = onLoadHandler;
20            var _this = this;
21            this._io = new IntersectionObserver(function(entries) {
22                _this.onIntersection(entries);
23            }, config);
24        }
25
26    }
27
28    Object.assign(JazelIntersectionObserver.prototype, {
29        getInstance: function() {
30            return this._io;
31        },
32        observe: function(node) {
33            this._io.observe(node);
34        },
35        unobserve: function(node) {
36            this._io.unobserve(node);
37        },
38        onIntersection: function(entries) {
39            // Loop through the entries
40            for (var i = 0; i < entries.length; i++) {
41                var entry = entries[i];
42                // Are we in viewport?
43                if (entry.intersectionRatio > 0) {
44                    entry.target.setAttribute(intersectAttribute, "true");
45                    var readyAttributeValue = entry.target.getAttribute(lazyReadyAttribute);
46                    var isReady;
47                    if (readyAttributeValue != null && readyAttributeValue !== "") {
48
49                        if (readyAttributeValue === "true") {
50                            isReady = true;
51                        } else if (readyAttributeValue === "false") {
52                            isReady = false;
53                        } else {
54                            console.warn("Unexpected value of " + lazyReadyAttribute + " attribute");
55                            isReady = true;
56                        }
57
58                    } else {
59                        // Default is true
60                        isReady = true;
61                    }
62
63                    if (isReady) {
64                        // Stop watching and load the image
65                        console.debug("Ready, Loading");
66                        this.unobserveAndLoad(entry.target);
67                    } else {
68                        console.debug("Not ready, not loading");
69                    }
70                } else {
71                    entry.target.removeAttribute(intersectAttribute);
72                }
73            }
74        },
75        unobserveAndLoad: function(node) {
76            node.removeAttribute(lazyReadyAttribute);
77            node.removeAttribute(intersectAttribute);
78            this._io.unobserve(node);
79            this._loadCallback(node);
80        },
81    });
82
83    window.JazelIntersectionObserver = JazelIntersectionObserver;
84
85})();