page-scroll.js
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import { isFunction } from '../common/validator';
import { getCurrentPage, isDef } from '../common/utils';
function onPageScroll(event) {
const { vanPageScroller = [] } = getCurrentPage();
vanPageScroller.forEach((scroller) => {
if (typeof scroller === 'function') {
// @ts-ignore
scroller(event);
}
});
}
export function pageScrollMixin(scroller) {
return Behavior({
attached() {
const page = getCurrentPage();
if (!isDef(page)) {
return;
}
const _scroller = scroller.bind(this);
const { vanPageScroller = [] } = page;
if (isFunction(page.onPageScroll) && page.onPageScroll !== onPageScroll) {
vanPageScroller.push(page.onPageScroll.bind(page));
}
vanPageScroller.push(_scroller);
page.vanPageScroller = vanPageScroller;
page.onPageScroll = onPageScroll;
this._scroller = _scroller;
},
detached() {
const page = getCurrentPage();
if (!isDef(page) || !isDef(page.vanPageScroller)) {
return;
}
const { vanPageScroller } = page;
const index = vanPageScroller.findIndex((v) => v === this._scroller);
if (index > -1) {
page.vanPageScroller.splice(index, 1);
}
this._scroller = undefined;
},
});
}