Updating url and title

When users are scrolling through pages we can update the browser url and page title. This allows the current page to be shared or bookmarked.
We can achieve this by listening for the page event. The page event contains the url and title of the current page in view.
The History API can be used to update the url.
ias.on('page', (event) => {
// update the title
document.title = event.title;
// update the url
let state = history.state;
history.replaceState(state, event.title, event.url);

Loading previous pages

Infinite Ajax Scroll can also be used to load items above the current scroll position. This is useful when you want to load older items first.