Create infScroll helper with reusable logic

based on the infinite scroll code from search page

src/lib/util/infScroll.ts

@@ -0,0 +1,64 @@
+export interface ToolTipOptions {
+	/**
+	 * Infinite scroll threshold.
+	 * Distance from bottom.
+	 */
+	threshold?: number;
+	/**
+	 * Ran when we reach the end of scroll.
+	 * This callback should load the new data.
+	 */
+	callback: () => Promise<void>;
+}
+
+/**
+ * Infinite scroll helper.
+ * Ensure `destroy` func is ran after the component
+ * this is used in is destroyed.
+ */
+export default function infScroll(opts: ToolTipOptions) {
+	let { threshold = 150, callback } = opts;
+
+	const addEvents = () => {
+		console.debug("infScroll->addEvents()");
+		window.addEventListener("scroll", run);
+		window.addEventListener("resize", run);
+	};
+
+	const removeEvents = () => {
+		console.debug("infScroll->removeEvents()");
+		window.removeEventListener("scroll", run);
+		window.removeEventListener("resize", run);
+	};
+
+	const isAtBottom = () => {
+		return (
+			window.innerHeight + Math.round(window.scrollY) + threshold >=
+			document.body.offsetHeight
+		);
+	};
+
+	const run = async () => {
+		console.debug("infiniteScroll()");
+		if (isAtBottom()) {
+			console.log("infiniteScroll: Reached end");
+			removeEvents();
+			await callback();
+			addEvents();
+			console.log("infiniteScroll: Callback ran");
+		} else {
+			console.debug("infiniteScroll: Not at bottom");
+		}
+	};
+
+	addEvents();
+
+	return {
+		isAtBottom,
+		run,
+		destroy: () => {
+			console.debug("infScroll->destroy()");
+			removeEvents();
+		},
+	};
+}