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/*! instant.page v1.2.2 - (C) 2019 Alexandre Dieulot - https://instant.page/license */
let urlToPreload;
let mouseoverTimer;
let lastTouchTimestamp;
const prefetcher = document.createElement("link");
const isSupported = prefetcher.relList && prefetcher.relList.supports && prefetcher.relList.supports("prefetch");
const isDataSaverEnabled = navigator.connection && navigator.connection.saveData;
const allowQueryString = "instantAllowQueryString" in document.body.dataset;
const allowExternalLinks = "instantAllowExternalLinks" in document.body.dataset;
if (isSupported && !isDataSaverEnabled) {
prefetcher.rel = "prefetch";
document.head.appendChild(prefetcher);
const eventListenersOptions = {
capture: true,
passive: true,
};
document.addEventListener("touchstart", touchstartListener, eventListenersOptions);
document.addEventListener("mouseover", mouseoverListener, eventListenersOptions)
}
function touchstartListener(event) {
/* Chrome on Android calls mouseover before touchcancel so `lastTouchTimestamp`
* must be assigned on touchstart to be measured on mouseover. */
lastTouchTimestamp = performance.now();
const linkElement = event.target.closest("tr[data-href]");
if (!isPreloadable(linkElement)) {
return
}
linkElement.addEventListener("touchcancel", touchendAndTouchcancelListener, {passive: true});
linkElement.addEventListener("touchend", touchendAndTouchcancelListener, {passive: true});
urlToPreload = window.location.href + linkElement.getAttribute("data-href");
preload(urlToPreload)
}
function touchendAndTouchcancelListener() {
urlToPreload = undefined;
stopPreloading()
}
function mouseoverListener(event) {
if (performance.now() - lastTouchTimestamp < 1100) {
return
}
const linkElement = event.target.closest("tr[data-href]");
if (!isPreloadable(linkElement)) {
return
}
linkElement.addEventListener("mouseout", mouseoutListener, {passive: true});
urlToPreload = window.location.href + linkElement.getAttribute("data-href");
mouseoverTimer = setTimeout(() => {
preload(urlToPreload);
mouseoverTimer = undefined
}, 65)
}
function mouseoutListener(event) {
if (event.relatedTarget && event.target.closest("tr[data-href]") === event.relatedTarget.closest("tr[data-href]")) {
return
}
if (mouseoverTimer) {
clearTimeout(mouseoverTimer);
mouseoverTimer = undefined
} else {
urlToPreload = undefined;
stopPreloading()
}
}
function isPreloadable(linkElement) {
if (!linkElement || !(window.location.href + linkElement.getAttribute("data-href"))) {
return
}
if (urlToPreload === window.location.href + linkElement.getAttribute("data-href")) {
return
}
const preloadLocation = new URL(window.location.href + linkElement.getAttribute("data-href"));
if (!allowExternalLinks && preloadLocation.origin !== location.origin && !("instant" in linkElement.dataset)) {
return
}
if (!["http:", "https:"].includes(preloadLocation.protocol)) {
return
}
if (preloadLocation.protocol === "http:" && location.protocol === "https:") {
return
}
if (!allowQueryString && preloadLocation.search && !("instant" in linkElement.dataset)) {
return
}
if (preloadLocation.hash && preloadLocation.pathname + preloadLocation.search === location.pathname + location.search) {
return
}
if ("noInstant" in linkElement.dataset) {
return
}
return true
}
function preload(url) {
prefetcher.href = url
}
function stopPreloading() {
prefetcher.removeAttribute("href")
}
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