https://skyticket.jp/js/googletagmanager_hack.js?dt=1790908740

1/**
2 * Monkey-patch for "querySelectorAll".
3 * 
4 * The goal is to temporarily replace the behaviour of "querySelectorAll".
5 * This global function is used inside the "www.googletagmanager.com/gtag" script to scan through all the 
6 * elements on the page, and use a regex to find emails (its end goal is to find external emails).
7 * But since this is TOO COSTLY, we hijack the behaviour to just return the elements that are holding external email info.
8 * So we need to tag some relevant elements with a class "has-external-email".
9 * 
10 * NOTE: We don't need to use it for all pages. We can only use it on the page where gtag is slow for some reasons.
11 * But if we do use it, we have to add the "has-external-email" classes in the right places.
12 */
13(function () {
14    const originalQSA = Element.prototype.querySelectorAll;
15    let qsaPatched = false;
16
17    /*
18    * Delay in ms.
19    * Put something like 1500 or 2000 if you want to just hijack the call that would happen on page load.
20    * Or put -1 -> "no restoring", ie: the patch stays applied
21    */
22    const DELAY_BEFORE_RESTORE = -1;
23
24    function patchQSA() {
25        if (qsaPatched) return;
26        qsaPatched = true;
27
28        Element.prototype.querySelectorAll = function (selector) {
29            // Detect Google's full-DOM scan
30            if (this === document.body && selector === "*") {
31                // Set for uniqueness
32                const elementsSet = new Set();
33
34                // Grab only return the elements YOU want Google to see
35                // -> root element is marked with class has-external-email
36                const roots = originalQSA.call(document.body, ".has-external-email");
37                roots.forEach(function (root) {
38                    elementsSet.add(root);
39
40                    // Include all descendants
41                    root.querySelectorAll("*")
42                        .forEach(function (descendant) {
43                            elementsSet.add(descendant);
44                        });
45                });
46
47                return Array.from(elementsSet);
48            }
49            return originalQSA.call(this, selector);
50        };
51    }
52
53    function restoreQSA() {
54        if (!qsaPatched) return;
55        qsaPatched = false;
56
57        Element.prototype.querySelectorAll = originalQSA;
58    }
59
60    // Install the patch immediately
61    patchQSA();
62
63    // Restore original behaviour after GTM/gtag email scanning is definitely done.
64    if (DELAY_BEFORE_RESTORE >= 0) {
65        window.addEventListener("load", () => {
66            setTimeout(() => {
67                restoreQSA();
68            }, DELAY_BEFORE_RESTORE);
69        });
70    }
71})();