Download raw (9.1 KB)
/**
* smooth-scroll v5.0.0
* Animate scrolling to anchor links, by Chris Ferdinandi.
* http://github.com/cferdinandi/smooth-scroll
*
* Free to use under the MIT License.
* http://gomakethings.com/mit/
*/
(function (root, factory) {
if ( typeof define === 'function' && define.amd ) {
define('smoothScroll', factory(root));
} else if ( typeof exports === 'object' ) {
module.smoothScroll = factory(root);
} else {
root.smoothScroll = factory(root);
}
})(this, function (root) {
'use strict';
//
// Variables
//
var exports = {}; // Object for public APIs
var supports = !!document.querySelector && !!root.addEventListener; // Feature test
var settings;
// Default settings
var defaults = {
speed: 500,
easing: 'easeInOutCubic',
offset: 0,
updateURL: true,
callbackBefore: function () {},
callbackAfter: function () {}
};
//
// Methods
//
/**
* A simple forEach() implementation for Arrays, Objects and NodeLists
* @private
* @param {Array|Object|NodeList} collection Collection of items to iterate
* @param {Function} callback Callback function for each iteration
* @param {Array|Object|NodeList} scope Object/NodeList/Array that forEach is iterating over (aka `this`)
*/
var forEach = function (collection, callback, scope) {
if (Object.prototype.toString.call(collection) === '[object Object]') {
for (var prop in collection) {
if (Object.prototype.hasOwnProperty.call(collection, prop)) {
callback.call(scope, collection[prop], prop, collection);
}
}
} else {
for (var i = 0, len = collection.length; i < len; i++) {
callback.call(scope, collection[i], i, collection);
}
}
};
/**
* Merge defaults with user options
* @private
* @param {Object} defaults Default settings
* @param {Object} options User options
* @returns {Object} Merged values of defaults and options
*/
var extend = function ( defaults, options ) {
var extended = {};
forEach(defaults, function (value, prop) {
extended[prop] = defaults[prop];
});
forEach(options, function (value, prop) {
extended[prop] = options[prop];
});
return extended;
};
/**
* Calculate the easing pattern
* @private
* @param {String} type Easing pattern
* @param {Number} time Time animation should take to complete
* @returns {Number}
*/
var easingPattern = function ( type, time ) {
var pattern;
if ( type === 'easeInQuad' ) pattern = time * time; // accelerating from zero velocity
if ( type === 'easeOutQuad' ) pattern = time * (2 - time); // decelerating to zero velocity
if ( type === 'easeInOutQuad' ) pattern = time < 0.5 ? 2 * time * time : -1 + (4 - 2 * time) * time; // acceleration until halfway, then deceleration
if ( type === 'easeInCubic' ) pattern = time * time * time; // accelerating from zero velocity
if ( type === 'easeOutCubic' ) pattern = (--time) * time * time + 1; // decelerating to zero velocity
if ( type === 'easeInOutCubic' ) pattern = time < 0.5 ? 4 * time * time * time : (time - 1) * (2 * time - 2) * (2 * time - 2) + 1; // acceleration until halfway, then deceleration
if ( type === 'easeInQuart' ) pattern = time * time * time * time; // accelerating from zero velocity
if ( type === 'easeOutQuart' ) pattern = 1 - (--time) * time * time * time; // decelerating to zero velocity
if ( type === 'easeInOutQuart' ) pattern = time < 0.5 ? 8 * time * time * time * time : 1 - 8 * (--time) * time * time * time; // acceleration until halfway, then deceleration
if ( type === 'easeInQuint' ) pattern = time * time * time * time * time; // accelerating from zero velocity
if ( type === 'easeOutQuint' ) pattern = 1 + (--time) * time * time * time * time; // decelerating to zero velocity
if ( type === 'easeInOutQuint' ) pattern = time < 0.5 ? 16 * time * time * time * time * time : 1 + 16 * (--time) * time * time * time * time; // acceleration until halfway, then deceleration
return pattern || time; // no easing, no acceleration
};
/**
* Calculate how far to scroll
* @private
* @param {Element} anchor The anchor element to scroll to
* @param {Number} headerHeight Height of a fixed header, if any
* @param {Number} offset Number of pixels by which to offset scroll
* @returns {Number}
*/
var getEndLocation = function ( anchor, headerHeight, offset ) {
var location = 0;
if (anchor.offsetParent) {
do {
location += anchor.offsetTop;
anchor = anchor.offsetParent;
} while (anchor);
}
location = location - headerHeight - offset;
return location >= 0 ? location : 0;
};
/**
* Determine the document's height
* @private
* @returns {Number}
*/
var getDocumentHeight = function () {
return Math.max(
document.body.scrollHeight, document.documentElement.scrollHeight,
document.body.offsetHeight, document.documentElement.offsetHeight,
document.body.clientHeight, document.documentElement.clientHeight
);
};
/**
* Convert data-options attribute into an object of key/value pairs
* @private
* @param {String} options Link-specific options as a data attribute string
* @returns {Object}
*/
var getDataOptions = function ( options ) {
return !options || !(typeof JSON === 'object' && typeof JSON.parse === 'function') ? {} : JSON.parse( options );
};
/**
* Update the URL
* @private
* @param {Element} anchor The element to scroll to
* @param {Boolean} url Whether or not to update the URL history
*/
var updateUrl = function ( anchor, url ) {
if ( history.pushState && (url || url === 'true') ) {
history.pushState( {
pos: anchor.id
}, '', window.location.pathname + anchor );
}
};
/**
* Start/stop the scrolling animation
* @public
* @param {Element} toggle The element that toggled the scroll event
* @param {Element} anchor The element to scroll to
* @param {Object} settings
* @param {Event} event
*/
exports.animateScroll = function ( toggle, anchor, options, event ) {
// Options and overrides
var settings = extend( settings || defaults, options || {} ); // Merge user options with defaults
var overrides = getDataOptions( toggle ? toggle.getAttribute('data-options') : null );
settings = extend( settings, overrides );
// Selectors and variables
var fixedHeader = document.querySelector('[data-scroll-header]'); // Get the fixed header
var headerHeight = fixedHeader === null ? 0 : (fixedHeader.offsetHeight + fixedHeader.offsetTop); // Get the height of a fixed header if one exists
var startLocation = root.pageYOffset; // Current location on the page
var endLocation = getEndLocation( document.querySelector(anchor), headerHeight, parseInt(settings.offset, 10) ); // Scroll to location
var animationInterval; // interval timer
var distance = endLocation - startLocation; // distance to travel
var documentHeight = getDocumentHeight();
var timeLapsed = 0;
var percentage, position;
// Prevent default click event
if ( toggle && toggle.tagName.toLowerCase() === 'a' && event ) {
event.preventDefault();
}
// Update URL
updateUrl(anchor, settings.updateURL);
/**
* Stop the scroll animation when it reaches its target (or the bottom/top of page)
* @private
* @param {Number} position Current position on the page
* @param {Number} endLocation Scroll to location
* @param {Number} animationInterval How much to scroll on this loop
*/
var stopAnimateScroll = function (position, endLocation, animationInterval) {
var currentLocation = root.pageYOffset;
if ( position == endLocation || currentLocation == endLocation || ( (root.innerHeight + currentLocation) >= documentHeight ) ) {
clearInterval(animationInterval);
settings.callbackAfter( toggle, anchor ); // Run callbacks after animation complete
}
};
/**
* Loop scrolling animation
* @private
*/
var loopAnimateScroll = function () {
timeLapsed += 16;
percentage = ( timeLapsed / parseInt(settings.speed, 10) );
percentage = ( percentage > 1 ) ? 1 : percentage;
position = startLocation + ( distance * easingPattern(settings.easing, percentage) );
root.scrollTo( 0, Math.floor(position) );
stopAnimateScroll(position, endLocation, animationInterval);
};
/**
* Set interval timer
* @private
*/
var startAnimateScroll = function () {
settings.callbackBefore( toggle, anchor ); // Run callbacks before animating scroll
animationInterval = setInterval(loopAnimateScroll, 16);
};
/**
* Reset position to fix weird iOS bug
* @link https://github.com/cferdinandi/smooth-scroll/issues/45
*/
if ( root.pageYOffset === 0 ) {
root.scrollTo( 0, 0 );
}
// Start scrolling animation
startAnimateScroll();
};
/**
* Initialize Smooth Scroll
* @public
* @param {Object} options User settings
*/
exports.init = function ( options ) {
// feature test
if ( !supports ) return;
// Selectors and variables
settings = extend( defaults, options || {} ); // Merge user options with defaults
var toggles = document.querySelectorAll('[data-scroll]'); // Get smooth scroll toggles
// When a toggle is clicked, run the click handler
forEach(toggles, function (toggle) {
toggle.addEventListener('click', exports.animateScroll.bind( null, toggle, toggle.hash, settings ), false);
});
};
//
// Public APIs
//
return exports;
});