calckey/packages/client/src/directives/follow-append.ts

40 lines
951 B
TypeScript

import { Directive } from "vue";
import { getScrollContainer, getScrollPosition } from "@/scripts/scroll";
export default {
mounted(src, binding, vn) {
if (binding.value === false) return;
let isBottom = true;
const container = getScrollContainer(src)!;
container.addEventListener(
"scroll",
() => {
const pos = getScrollPosition(container);
const viewHeight = container.clientHeight;
const height = container.scrollHeight;
isBottom = pos + viewHeight > height - 32;
},
{ passive: true },
);
container.scrollTop = container.scrollHeight;
const ro = new ResizeObserver((entries, observer) => {
if (isBottom) {
const height = container.scrollHeight;
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) {
if (src._ro_) src._ro_.unobserve(src);
},
} as Directive;