Improve task manager etc

src/client/directives/follow-append.ts

@@ -0,0 +1,25 @@
+import { Directive } from 'vue';
+import { getScrollContainer, getScrollPosition } from '@/scripts/scroll';
+
+export default {
+	mounted(src, binding, vn) {
+		const ro = new ResizeObserver((entries, observer) => {
+			const pos = getScrollPosition(src);
+			const container = getScrollContainer(src);
+			const viewHeight = container.clientHeight;
+			const height = container.scrollHeight;
+			if (pos + viewHeight > height - 32) {
+				container.scrollTop = height;
+			}
+		});
+
+		ro.observe(src);
+
+		// TODO: 新たにプロパティを作るのをやめMapを使う
+		src._ro_ = ro;
+	},
+
+	unmounted(src, binding, vn) {
+		src._ro_.unobserve(src);
+	}
+} as Directive;