Refactor: Extract scroll utility functions

src/client/scripts/paging.ts

@@ -1,32 +1,5 @@
 import Vue from 'vue';
-
-function getScrollContainer(el: Element | null): Element | null {
-	if (el == null || el.tagName === 'BODY') return null;
-	const style = window.getComputedStyle(el);
-	if (style.getPropertyValue('overflow') === 'auto') {
-		return el;
-	} else {
-		return getScrollContainer(el.parentElement);
-	}
-}
-
-function getScrollPosition(el: Element | null): number {
-	const container = getScrollContainer(el);
-	return container == null ? window.scrollY : container.scrollTop;
-}
-
-function onScrollTop(el, cb) {
-	const container = getScrollContainer(el) || window;
-	const onScroll = ev => {
-		if (!document.body.contains(el)) return;
-		const pos = getScrollPosition(el);
-		if (pos === 0) {
-			cb();
-			container.removeEventListener('scroll', onscroll);
-		}
-	};
-	container.addEventListener('scroll', onScroll, { passive: true });
-}
+import { getScrollPosition, onScrollTop } from './scroll';
 
 const SECOND_FETCH_LIMIT = 30;
 

src/client/scripts/scroll.ts

@@ -0,0 +1,27 @@
+export function getScrollContainer(el: Element | null): Element | null {
+	if (el == null || el.tagName === 'BODY') return null;
+	const style = window.getComputedStyle(el);
+	if (style.getPropertyValue('overflow') === 'auto') {
+		return el;
+	} else {
+		return getScrollContainer(el.parentElement);
+	}
+}
+
+export function getScrollPosition(el: Element | null): number {
+	const container = getScrollContainer(el);
+	return container == null ? window.scrollY : container.scrollTop;
+}
+
+export function onScrollTop(el: Element, cb) {
+	const container = getScrollContainer(el) || window;
+	const onScroll = ev => {
+		if (!document.body.contains(el)) return;
+		const pos = getScrollPosition(el);
+		if (pos === 0) {
+			cb();
+			container.removeEventListener('scroll', onscroll);
+		}
+	};
+	container.addEventListener('scroll', onScroll, { passive: true });
+}