.
*
* The individual post items are extracted from the fetched pages by looking for
* a wrapper element with the class "post-card". Any found elements are appended
* to the element with the class "post-feed" in the currently viewed page.
*/
(function (window, document) {
// next link element
var nextElement = document.querySelector('link[rel=next]');
if (!nextElement) {
return;
}
// post feed element
var feedElement = document.querySelector('.post-feed');
if (!feedElement) {
return;
}
var buffer = 300;
var ticking = false;
var loading = false;
var lastScrollY = window.scrollY;
var lastWindowHeight = window.innerHeight;
var lastDocumentHeight = document.documentElement.scrollHeight;
function onPageLoad() {
if (this.status === 404) {
window.removeEventListener('scroll', onScroll);
window.removeEventListener('resize', onResize);
return;
}
// append contents
var postElements = this.response.querySelectorAll('article.post-card');
postElements.forEach(function (item) {
// document.importNode is important, without it the item's owner
// document will be different which can break resizing of
// `object-fit: cover` images in Safari
feedElement.appendChild(document.importNode(item, true));
});
// set next link
var resNextElement = this.response.querySelector('link[rel=next]');
if (resNextElement) {
nextElement.href = resNextElement.href;
} else {
window.removeEventListener('scroll', onScroll);
window.removeEventListener('resize', onResize);
}
// sync status
lastDocumentHeight = document.documentElement.scrollHeight;
ticking = false;
loading = false;
}
function onUpdate() {
// return if already loading
if (loading) {
return;
}
// return if not scroll to the bottom
if (lastScrollY + lastWindowHeight <= lastDocumentHeight - buffer) {
ticking = false;
return;
}
loading = true;
var xhr = new window.XMLHttpRequest();
xhr.responseType = 'document';
xhr.addEventListener('load', onPageLoad);
xhr.open('GET', nextElement.href);
xhr.send(null);
}
function requestTick() {
ticking || window.requestAnimationFrame(onUpdate);
ticking = true;
}
function onScroll() {
lastScrollY = window.scrollY;
requestTick();
}
function onResize() {
lastWindowHeight = window.innerHeight;
lastDocumentHeight = document.documentElement.scrollHeight;
requestTick();
}
window.addEventListener('scroll', onScroll, {passive: true});
window.addEventListener('resize', onResize);
requestTick();
})(window, document);
