hexo/node_modules/smoothscroll/smoothscroll.js

121 lines
4.3 KiB
JavaScript

(function (root, smoothScroll) {
'use strict';
// Support RequireJS and CommonJS/NodeJS module formats.
// Attach smoothScroll to the `window` when executed as a <script>.
// RequireJS
if (typeof define === 'function' && define.amd) {
define(smoothScroll);
// CommonJS
} else if (typeof exports === 'object' && typeof module === 'object') {
module.exports = smoothScroll();
} else {
root.smoothScroll = smoothScroll();
}
})(this, function(){
'use strict';
// Do not initialize smoothScroll when running server side, handle it in client:
if (typeof window !== 'object') return;
// We do not want this script to be applied in browsers that do not support those
// That means no smoothscroll on IE9 and below.
if(document.querySelectorAll === void 0 || window.pageYOffset === void 0 || history.pushState === void 0) { return; }
// Get the top position of an element in the document
var getTop = function(element, start) {
// return value of html.getBoundingClientRect().top ... IE : 0, other browsers : -pageYOffset
if(element.nodeName === 'HTML') return -start
return element.getBoundingClientRect().top + start
}
// ease in out function thanks to:
// http://blog.greweb.fr/2012/02/bezier-curve-based-easing-functions-from-concept-to-implementation/
var easeInOutCubic = function (t) { return t<.5 ? 4*t*t*t : (t-1)*(2*t-2)*(2*t-2)+1 }
// calculate the scroll position we should be in
// given the start and end point of the scroll
// the time elapsed from the beginning of the scroll
// and the total duration of the scroll (default 500ms)
var position = function(start, end, elapsed, duration) {
if (elapsed > duration) return end;
return start + (end - start) * easeInOutCubic(elapsed / duration); // <-- you can change the easing funtion there
// return start + (end - start) * (elapsed / duration); // <-- this would give a linear scroll
}
// we use requestAnimationFrame to be called by the browser before every repaint
// if the first argument is an element then scroll to the top of this element
// if the first argument is numeric then scroll to this location
// if the callback exist, it is called when the scrolling is finished
// if context is set then scroll that element, else scroll window
var smoothScroll = function(el, duration, callback, context){
duration = duration || 500;
context = context || window;
var start = context.scrollTop || window.pageYOffset;
if (typeof el === 'number') {
var end = parseInt(el);
} else {
var end = getTop(el, start);
}
var clock = Date.now();
var requestAnimationFrame = window.requestAnimationFrame ||
window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame ||
function(fn){window.setTimeout(fn, 15);};
var step = function(){
var elapsed = Date.now() - clock;
if (context !== window) {
context.scrollTop = position(start, end, elapsed, duration);
}
else {
window.scroll(0, position(start, end, elapsed, duration));
}
if (elapsed > duration) {
if (typeof callback === 'function') {
callback(el);
}
} else {
requestAnimationFrame(step);
}
}
step();
}
var linkHandler = function(ev) {
if (!ev.defaultPrevented) {
ev.preventDefault();
if (location.hash !== this.hash) window.history.pushState(null, null, this.hash)
// using the history api to solve issue #1 - back doesn't work
// most browser don't update :target when the history api is used:
// THIS IS A BUG FROM THE BROWSERS.
// change the scrolling duration in this call
var node = document.getElementById(this.hash.substring(1))
if (!node) return; // Do not scroll to non-existing node
smoothScroll(node, 500, function (el) {
location.replace('#' + el.id)
// this will cause the :target to be activated.
});
}
}
// We look for all the internal links in the documents and attach the smoothscroll function
document.addEventListener("DOMContentLoaded", function () {
var internal = document.querySelectorAll('a[href^="#"]:not([href="#"])'), a;
for(var i=internal.length; a=internal[--i];){
a.addEventListener("click", linkHandler, false);
}
});
// return smoothscroll API
return smoothScroll;
});