50 lines
1.2 KiB
JavaScript
50 lines
1.2 KiB
JavaScript
import { raf, cancelRaf } from "@vant/use";
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import { getScrollTop, setScrollTop } from "../utils/index.mjs";
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function scrollLeftTo(scroller, to, duration) {
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let rafId;
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let count = 0;
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const from = scroller.scrollLeft;
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const frames = duration === 0 ? 1 : Math.round(duration * 1e3 / 16);
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let scrollLeft = from;
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function cancel() {
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cancelRaf(rafId);
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}
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function animate() {
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scrollLeft += (to - from) / frames;
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scroller.scrollLeft = scrollLeft;
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if (++count < frames) {
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rafId = raf(animate);
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}
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}
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animate();
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return cancel;
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}
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function scrollTopTo(scroller, to, duration, callback) {
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let rafId;
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let current = getScrollTop(scroller);
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const isDown = current < to;
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const frames = duration === 0 ? 1 : Math.round(duration * 1e3 / 16);
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const step = (to - current) / frames;
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function cancel() {
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cancelRaf(rafId);
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}
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function animate() {
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current += step;
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if (isDown && current > to || !isDown && current < to) {
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current = to;
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}
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setScrollTop(scroller, current);
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if (isDown && current < to || !isDown && current > to) {
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rafId = raf(animate);
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} else if (callback) {
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rafId = raf(callback);
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}
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}
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animate();
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return cancel;
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}
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export {
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scrollLeftTo,
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scrollTopTo
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};
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