Method scrollTo

site/src/javascript/Scroll.js:44–80

* Scroll to value with transition * @param {Number} scrollTargetY Scroll value * @param {Number} speed Speed

(scrollTargetY = 0, speed = 2000)

     * @param {Number} speed Speed
     */
    scrollTo(scrollTargetY = 0, speed = 2000)
    {
        // Set up
        const scrollY = window.scrollY || document.documentElement.scrollTop
        let currentTime = 0
        const time = Math.max(.1, Math.min(Math.abs(scrollY - scrollTargetY) / speed, .8))

        // EaseInOutQuint
        const easeInOutQuint = (pos) =>
        {
            if ((pos /= 0.5) < 1) {
                return 0.5 * Math.pow(pos, 5);
            }
            return 0.5 * (Math.pow((pos - 2), 5) + 2);
        }

        // Tick
        const tick = () =>
        {
            currentTime += 1 / 60

            const p = currentTime / time
            const t = easeInOutQuint(p)

            if(p < 1)
            {
                window.requestAnimationFrame(tick)
                window.scrollTo(0, scrollY + ((scrollTargetY - scrollY) * t))
            }
            else
            {
                window.scrollTo(0, scrollTargetY)
            }
        }

        tick()
    }
}