vant-weapp/dist/collapse-item/animate.js

import { canIUseAnimate } from '../common/version';
import { getRect } from '../common/utils';
function useAnimate(context, expanded, mounted, height) {
    const selector = '.van-collapse-item__wrapper';
    if (expanded) {
        context.animate(selector, [
            { height: 0, ease: 'ease-in-out', offset: 0 },
            { height: `${height}px`, ease: 'ease-in-out', offset: 1 },
            { height: `auto`, ease: 'ease-in-out', offset: 1 },
        ], mounted ? 300 : 0, () => {
            context.clearAnimation(selector);
        });
        return;
    }
    context.animate(selector, [
        { height: `${height}px`, ease: 'ease-in-out', offset: 0 },
        { height: 0, ease: 'ease-in-out', offset: 1 },
    ], 300, () => {
        context.clearAnimation(selector);
    });
}
function useAnimation(context, expanded, mounted, height) {
    const animation = wx.createAnimation({
        duration: 0,
        timingFunction: 'ease-in-out',
    });
    if (expanded) {
        if (height === 0) {
            animation.height('auto').top(1).step();
        }
        else {
            animation
                .height(height)
                .top(1)
                .step({
                duration: mounted ? 300 : 1,
            })
                .height('auto')
                .step();
        }
        context.setData({
            animation: animation.export(),
        });
        return;
    }
    animation.height(height).top(0).step({ duration: 1 }).height(0).step({
        duration: 300,
    });
    context.setData({
        animation: animation.export(),
    });
}
export function setContentAnimate(context, expanded, mounted) {
    getRect(context, '.van-collapse-item__content')
        .then((rect) => rect.height)
        .then((height) => {
        canIUseAnimate()
            ? useAnimate(context, expanded, mounted, height)
            : useAnimation(context, expanded, mounted, height);
    });
}