// 缓动到某位置
export default function linearScrollTo(yAxis, duration = 500){
    const startTime = +new Date();
    const oTop = window.pageYOffset;
    const dis = yAxis - oTop;
    let timer = requestAnimationFrame(function func() {
        const t = duration - Math.max(0, startTime + duration - (+new Date()));
        window.scrollTo(0, t * dis / duration + oTop)
        timer = requestAnimationFrame(func);
        if (t === duration) {
            cancelAnimationFrame(timer);
        }
    });
}