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switched/src/client/directives/follow-append.ts
2021-03-23 17:30:14 +09:00

36 lines
939 B
TypeScript

import { Directive } from 'vue';
import { getScrollContainer, getScrollPosition } from '@client/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;