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(function () {
const cookiesDisabled = !navigator.cookieEnabled;
if (cookiesDisabled) {
document.cookie = "disabled";
document.cookie.indexOf("disabled");
return console.log("Pager is disabled due to cookie restrictions.");
}
const settings = { pager: {} };
const url = self.location.href.split("#")[0].split("?")[0];
const scrollRestore = (settings, url) => {
if (history.scrollRestoration) history.scrollRestoration = "manual";
if (localStorage["settings"]) {
settings = JSON.parse(localStorage["settings"]);
}
const fragment = document.getElementById(location.hash.slice(1));
const fragmentInURL = self.location.hash.length > 0;
if (fragmentInURL && document.body.contains(fragment)) {
settings["pager"][url] = self.pageYOffset;
localStorage["settings"] = JSON.stringify(settings);
fragment.scrollIntoView();
self.addEventListener("load", function () {
fragment.scrollIntoView();
});
return;
}
if (settings["pager"][url] > 0) {
self.scrollTo(0, settings["pager"][url]);
return;
}
settings["pager"][url] = self.pageYOffset;
localStorage["settings"] = JSON.stringify(settings);
};
const scrollTrack = (settings, url) => {
const currentPosition = self.pageYOffset;
settings["pager"][url] = currentPosition;
localStorage["settings"] = JSON.stringify(settings);
};
const backTrack = (back, up, event) => {
if (document.body.contains(up) && up.contains(event.target)) {
event.preventDefault();
window.scrollTo(0, 0);
}
if (document.body.contains(back) && back.contains(event.target)) {
if (history.length < 2) return;
event.preventDefault();
history.go(-1);
}
};
const fragmentClear = (entries) => {
for (let entry = 0; entry < entries.length; entry++) {
if (self.location.hash) {
self.history.pushState(null, "", url);
}
}
};
const fragmentRelease = (fragmentCallback) => {
try {
const fragmentObserver = new IntersectionObserver(fragmentCallback, {
threshold: 1.0,
});
const fragments = document.querySelectorAll("[id]");
for (let fragment = 0; fragment < fragments.length; fragment++) {
fragmentObserver.observe(fragments[fragment]);
}
} catch (error) {
console.log("The intersection observer is not supported", error);
}
};
self.addEventListener("DOMContentLoaded", function () {
scrollRestore(settings, url);
fragmentRelease(fragmentClear);
self.addEventListener("click", function (event) {
const up = document.getElementById("top");
const back = document.getElementById("back");
backTrack(back, up, event);
});
});
self.addEventListener("scroll", function () {
scrollTrack(settings, url);
});
})();
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