scrollTo滾動效果

Math.easeInOutQuad = function (t, b, c, d) {
t /= d / 2
if (t < 1) {

return c / 2 * t * t + b

}
t--
return -c / 2 (t (t - 2) - 1) + b
}

// requestAnimationFrame for Smart Animating http://goo.gl/sx5sts
var requestAnimFrame = (function () {
return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function (callback) { window.setTimeout(callback, 1000 / 60) }
})()

/**

• Because it's so fucking difficult to detect the scrolling element, just move them all
• @param {number} amount

*/
function move(amount, domTarget) {
if (domTarget && document.querySelector(domTarget)) {

document.querySelector(domTarget).scrollTop = amount

} else if (document.querySelector('.base')) {

document.querySelector('.base').scrollTop = amount

}
document.documentElement.scrollTop = amount
document.body.parentNode.scrollTop = amount
document.body.scrollTop = amount
}

function position(domTarget) {
if (domTarget && document.querySelector(domTarget)) {

return document.querySelector(domTarget).scrollTop || document.documentElement.scrollTop || document.body.parentNode.scrollTop || document.body.scrollTop

}
return document.querySelector('.base') && document.querySelector('.base').scrollTop || document.documentElement.scrollTop || document.body.parentNode.scrollTop || document.body.scrollTop
}

/**

• @param {number} to
• @param {number} duration
• @param {Function} callback

*/
export function scrollTo(to, duration, callback, domTarget) {
const start = position(domTarget)
const change = to - start
const increment = 20
let currentTime = 0
duration = (typeof (duration) === 'undefined') ? 500 : duration
var animateScroll = function () {

// increment the time
currentTime += increment
// find the value with the quadratic in-out easing function
var val = Math.easeInOutQuad(currentTime, start, change, duration)
// move the document.body
move(val, domTarget)
// do the animation unless its over
if (currentTime < duration) {
  requestAnimFrame(animateScroll)
} else {
  if (callback && typeof (callback) === 'function') {
    // the animation is done so lets callback
    callback()
  }
}

}
animateScroll()
}

// 代碼中使用// import { scrollTo } from "Tools/scroll-to";// scrollTo(0, 1600, '', '.target');