Math.easeInOutQuad = function(t, b, c, d) {
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t /= d / 2;
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if (t < 1) {
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return c / 2 * t * t + b;
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}
|
t--;
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return -c / 2 * (t * (t - 2) - 1) + b;
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};
|
|
// requestAnimationFrame for Smart Animating http://goo.gl/sx5sts
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var requestAnimFrame = (function() {
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return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function(callback) { window.setTimeout(callback, 1000 / 60); };
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})();
|
|
// because it's so fucking difficult to detect the scrolling element, just move them all
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function move(amount) {
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document.documentElement.scrollTop = amount;
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document.body.parentNode.scrollTop = amount;
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document.body.scrollTop = amount;
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}
|
|
function position() {
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return document.documentElement.scrollTop || document.body.parentNode.scrollTop || document.body.scrollTop;
|
}
|
|
export function scrollTo(to, duration, callback) {
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const start = position();
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const change = to - start;
|
const increment = 20;
|
let currentTime = 0;
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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);
|
// 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();
|
}
|
