/**
* Sticky Sidebar JavaScript Plugin.
* @version 3.3.4
* @author Ahmed Bouhuolia <a.bouhuolia@gmail.com>
* @license The MIT License (MIT)
*/
const StickySidebar = (() => {
// ---------------------------------
// # Define Constants
// ---------------------------------
//
const EVENT_KEY = '.stickySidebar';
const VERSION = '3.3.4';
const DEFAULTS = {
/**
* Additional top spacing of the element when it becomes sticky.
* @type {Numeric|Function}
*/
topSpacing: 0,
/**
* Additional bottom spacing of the element when it becomes sticky.
* @type {Numeric|Function}
*/
bottomSpacing: 0,
/**
* Container sidebar selector to know what the beginning and end of sticky element.
* @type {String|False}
*/
containerSelector: false,
/**
* Inner wrapper selector.
* @type {String}
*/
innerWrapperSelector: '.inner-wrapper-sticky',
/**
* The name of CSS class to apply to elements when they have become stuck.
* @type {String|False}
*/
stickyClass: 'is-affixed',
/**
* Detect when sidebar and its container change height so re-calculate their dimensions.
* @type {Boolean}
*/
resizeSensor: true,
/**
* The sidebar returns to its normal position if its width below this value.
* @type {Numeric}
*/
minWidth: false
};
// ---------------------------------
// # Class Definition
// ---------------------------------
//
/**
* Sticky Sidebar Class.
* @public
*/
class StickySidebar{
/**
* Sticky Sidebar Constructor.
* @constructor
* @param {HTMLElement|String} sidebar - The sidebar element or sidebar selector.
* @param {Object} options - The options of sticky sidebar.
*/
constructor(sidebar, options = {}){
this.options = StickySidebar.extend(DEFAULTS, options);
// Sidebar element query if there's no one, throw error.
this.sidebar = ('string' === typeof sidebar ) ? document.querySelector(sidebar) : sidebar;
if( 'undefined' === typeof this.sidebar )
throw new Error("There is no specific sidebar element.");
this.sidebarInner = false;
this.container = this.sidebar.parentElement;
// Current Affix Type of sidebar element.
this.affixedType = 'STATIC';
this.direction = 'down';
this.support = {
transform: false,
transform3d: false
};
this._initialized = false;
this._reStyle = false;
this._breakpoint = false;
// Dimensions of sidebar, container and screen viewport.
this.dimensions = {
translateY: 0,
maxTranslateY: 0,
topSpacing: 0,
lastTopSpacing: 0,
bottomSpacing: 0,
lastBottomSpacing: 0,
sidebarHeight: 0,
sidebarWidth: 0,
containerTop: 0,
containerHeight: 0,
viewportHeight: 0,
viewportTop: 0,
lastViewportTop: 0,
};
// Bind event handlers for referencability.
['handleEvent'].forEach( (method) => {
this[method] = this[method].bind(this);
});
// Initialize sticky sidebar for first time.
this.initialize();
}
/**
* Initializes the sticky sidebar by adding inner wrapper, define its container,
* min-width breakpoint, calculating dimensions, adding helper classes and inline style.
* @private
*/
initialize(){
this._setSupportFeatures();
// Get sticky sidebar inner wrapper, if not found, will create one.
if( this.options.innerWrapperSelector ){
this.sidebarInner = this.sidebar.querySelector(this.options.innerWrapperSelector);
if( null === this.sidebarInner )
this.sidebarInner = false;
}
if( ! this.sidebarInner ){
let wrapper = document.createElement('div');
wrapper.setAttribute('class', 'inner-wrapper-sticky');
this.sidebar.appendChild(wrapper);
while( this.sidebar.firstChild != wrapper )
wrapper.appendChild(this.sidebar.firstChild);
this.sidebarInner = this.sidebar.querySelector('.inner-wrapper-sticky');
}
// Container wrapper of the sidebar.
if( this.options.containerSelector ){
let containers = document.querySelectorAll(this.options.containerSelector);
containers = Array.prototype.slice.call(containers);
containers.forEach((container, item) => {
if( ! container.contains(this.sidebar) ) return;
this.container = container;
});
if( ! containers.length )
throw new Error("The container does not contains on the sidebar.");
}
// If top/bottom spacing is not function parse value to integer.
if( 'function' !== typeof this.options.topSpacing )
this.options.topSpacing = parseInt(this.options.topSpacing) || 0;
if( 'function' !== typeof this.options.bottomSpacing )
this.options.bottomSpacing = parseInt(this.options.bottomSpacing) || 0;
// Breakdown sticky sidebar if screen width below `options.minWidth`.
this._widthBreakpoint();
// Calculate dimensions of sidebar, container and viewport.
this.calcDimensions();
// Affix sidebar in proper position.
this.stickyPosition();
// Bind all events.
this.bindEvents();
// Inform other properties the sticky sidebar is initialized.
this._initialized = true;
}
/**
* Bind all events of sticky sidebar plugin.
* @protected
*/
bindEvents(){
window.addEventListener('resize', this, {passive: true, capture: false});
window.addEventListener('scroll', this, {passive: true, capture: false});
this.sidebar.addEventListener('update' + EVENT_KEY, this);
if( this.options.resizeSensor && 'undefined' !== typeof ResizeSensor ){
new ResizeSensor(this.sidebarInner, this.handleEvent);
new ResizeSensor(this.container, this.handleEvent);
}
}
/**
* Handles all events of the plugin.
* @param {Object} event - Event object passed from listener.
*/
handleEvent(event){
this.updateSticky(event);
}
/**
* Calculates dimensions of sidebar, container and screen viewpoint
* @public
*/
calcDimensions(){
if( this._breakpoint ) return;
var dims = this.dimensions;
// Container of sticky sidebar dimensions.
dims.containerTop = StickySidebar.offsetRelative(this.container).top;
dims.containerHeight = this.container.clientHeight;
dims.containerBottom = dims.containerTop + dims.containerHeight;
// Sidebar dimensions.
dims.sidebarHeight = this.sidebarInner.offsetHeight;
dims.sidebarWidth = this.sidebarInner.offsetWidth;
// Screen viewport dimensions.
dims.viewportHeight = window.innerHeight;
// Maximum sidebar translate Y.
dims.maxTranslateY = dims.containerHeight - dims.sidebarHeight;
this._calcDimensionsWithScroll();
}
/**
* Some dimensions values need to be up-to-date when scrolling the page.
* @private
*/
_calcDimensionsWithScroll(){
var dims = this.dimensions;
dims.sidebarLeft = StickySidebar.offsetRelative(this.sidebar).left;
dims.viewportTop = document.documentElement.scrollTop || document.body.scrollTop;
dims.viewportBottom = dims.viewportTop + dims.viewportHeight;
dims.viewportLeft = document.documentElement.scrollLeft || document.body.scrollLeft;
dims.topSpacing = this.options.topSpacing;
dims.bottomSpacing = this.options.bottomSpacing;
if( 'function' === typeof dims.topSpacing )
dims.topSpacing = parseInt(dims.topSpacing(this.sidebar)) || 0;
if( 'function' === typeof dims.bottomSpacing )
dims.bottomSpacing = parseInt(dims.bottomSpacing(this.sidebar)) || 0;
if( 'VIEWPORT-TOP' === this.affixedType ){
// Adjust translate Y in the case decrease top spacing value.
if( dims.topSpacing < dims.lastTopSpacing ){
dims.translateY += dims.lastTopSpacing - dims.topSpacing;
this._reStyle = true;
}
} else if( 'VIEWPORT-BOTTOM' === this.affixedType ){
// Adjust translate Y in the case decrease bottom spacing value.
if( dims.bottomSpacing < dims.lastBottomSpacing ){
dims.translateY += dims.lastBottomSpacing - dims.bottomSpacing;
this._reStyle = true;
}
}
dims.lastTopSpacing = dims.topSpacing;
dims.lastBottomSpacing = dims.bottomSpacing;
}
/**
* Determine whether the sidebar is bigger than viewport.
* @public
* @return {Boolean}
*/
isSidebarFitsViewport(){
let dims = this.dimensions;
let offset = this.scrollDirection === 'down' ? dims.lastBottomSpacing : dims.lastTopSpacing;
return this.dimensions.sidebarHeight + offset < this.dimensions.viewportHeight;
}
/**
* Observe browser scrolling direction top and down.
*/
observeScrollDir(){
var dims = this.dimensions;
if( dims.lastViewportTop === dims.viewportTop ) return;
var furthest = 'down' === this.direction ? Math.min : Math.max;
// If the browser is scrolling not in the same direction.
if( dims.viewportTop === furthest(dims.viewportTop, dims.lastViewportTop) )
this.direction = 'down' === this.direction ? 'up' : 'down';
}
/**
* Gets affix type of sidebar according to current scroll top and scrolling direction.
* @public
* @return {String|False} - Proper affix type.
*/
getAffixType(){
this._calcDimensionsWithScroll();
var dims = this.dimensions;
var colliderTop = dims.viewportTop + dims.topSpacing;
var affixType = this.affixedType;
if( colliderTop <= dims.containerTop || dims.containerHeight <= dims.sidebarHeight ){
dims.translateY = 0;
affixType = 'STATIC';
} else {
affixType = ( 'up' === this.direction ) ?
this._getAffixTypeScrollingUp() : this._getAffixTypeScrollingDown();
}
// Make sure the translate Y is not bigger than container height.
dims.translateY = Math.max(0, dims.translateY);
dims.translateY = Math.min(dims.containerHeight, dims.translateY);
dims.translateY = Math.round(dims.translateY);
dims.lastViewportTop = dims.viewportTop;
return affixType;
}
/**
* Get affix type while scrolling down.
* @private
* @return {String} - Proper affix type of scrolling down direction.
*/
_getAffixTypeScrollingDown(){
var dims = this.dimensions;
var sidebarBottom = dims.sidebarHeight + dims.containerTop;
var colliderTop = dims.viewportTop + dims.topSpacing;
var colliderBottom = dims.viewportBottom - dims.bottomSpacing;
var affixType = this.affixedType;
if( this.isSidebarFitsViewport() ){
if( dims.sidebarHeight + colliderTop >= dims.containerBottom ){
dims.translateY = dims.containerBottom - sidebarBottom;
affixType = 'CONTAINER-BOTTOM';
} else if( colliderTop >= dims.containerTop ){
dims.translateY = colliderTop - dims.containerTop;
affixType = 'VIEWPORT-TOP';
}
} else {
if( dims.containerBottom <= colliderBottom ){
dims.translateY = dims.containerBottom - sidebarBottom;
affixType = 'CONTAINER-BOTTOM';
} else if( sidebarBottom + dims.translateY <= colliderBottom ){
dims.translateY = colliderBottom - sidebarBottom;
affixType = 'VIEWPORT-BOTTOM';
} else if( dims.containerTop + dims.translateY <= colliderTop &&
(0 !== dims.translateY && dims.maxTranslateY !== dims.translateY) ){
affixType = 'VIEWPORT-UNBOTTOM';
}
}
return affixType;
}
/**
* Get affix type while scrolling up.
* @private
* @return {String} - Proper affix type of scrolling up direction.
*/
_getAffixTypeScrollingUp(){
var dims = this.dimensions;
var sidebarBottom = dims.sidebarHeight + dims.containerTop;
var colliderTop = dims.viewportTop + dims.topSpacing;
var colliderBottom = dims.viewportBottom - dims.bottomSpacing;
var affixType = this.affixedType;
if( colliderTop <= dims.translateY + dims.containerTop ){
dims.translateY = colliderTop - dims.containerTop;
affixType = 'VIEWPORT-TOP';
} else if( dims.containerBottom <= colliderBottom ){
dims.translateY = dims.containerBottom - sidebarBottom;
affixType = 'CONTAINER-BOTTOM';
} else if( ! this.isSidebarFitsViewport() ){
if( dims.containerTop <= colliderTop &&
(0 !== dims.translateY && dims.maxTranslateY !== dims.translateY) ){
affixType = 'VIEWPORT-UNBOTTOM';
}
}
return affixType;
}
/**
* Gets inline style of sticky sidebar wrapper and inner wrapper according
* to its affix type.
* @private
* @param {String} affixType - Affix type of sticky sidebar.
* @return {Object}
*/
_getStyle(affixType){
if( 'undefined' === typeof affixType ) return;
var style = {inner: {}, outer: {}};
var dims = this.dimensions;
switch( affixType ){
case 'VIEWPORT-TOP':
style.inner = {position: 'fixed', top: dims.topSpacing,
left: dims.sidebarLeft - dims.viewportLeft, width: dims.sidebarWidth};
break;
case 'VIEWPORT-BOTTOM':
style.inner = {position: 'fixed', top: 'auto', left: dims.sidebarLeft,
bottom: dims.bottomSpacing, width: dims.sidebarWidth};
break;
case 'CONTAINER-BOTTOM':
case 'VIEWPORT-UNBOTTOM':
let translate = this._getTranslate(0, dims.translateY + 'px');
if( translate )
style.inner = {transform: translate};
else
style.inner = {position: 'absolute', top: dims.translateY, width: dims.sidebarWidth};
break;
}
switch( affixType ){
case 'VIEWPORT-TOP':
case 'VIEWPORT-BOTTOM':
case 'VIEWPORT-UNBOTTOM':
case 'CONTAINER-BOTTOM':
style.outer = {height: dims.sidebarHeight, position: 'relative'};
break;
}
style.outer = StickySidebar.extend({height: '', position: ''}, style.outer);
style.inner = StickySidebar.extend({position: 'relative', top: '', left: '',
bottom: '', width: '', transform: ''}, style.inner);
return style;
}
/**
* Cause the sidebar to be sticky according to affix type by adding inline
* style, adding helper class and trigger events.
* @function
* @protected
* @param {string} force - Update sticky sidebar position by force.
*/
stickyPosition(force){
if( this._breakpoint ) return;
force = this._reStyle || force || false;
var offsetTop = this.options.topSpacing;
var offsetBottom = this.options.bottomSpacing;
var affixType = this.getAffixType();
var style = this._getStyle(affixType);
if( (this.affixedType != affixType || force) && affixType ){
let affixEvent = 'affix.' + affixType.toLowerCase().replace('viewport-', '') + EVENT_KEY;
StickySidebar.eventTrigger(this.sidebar, affixEvent);
if( 'STATIC' === affixType )
StickySidebar.removeClass(this.sidebar, this.options.stickyClass);
else
StickySidebar.addClass(this.sidebar, this.options.stickyClass);
for( let key in style.outer ){
let unit = ('number' === typeof style.outer[key]) ? 'px' : '';
this.sidebar.style[key] = style.outer[key] + unit;
}
for( let key in style.inner ){
let unit = ('number' === typeof style.inner[key]) ? 'px' : '';
this.sidebarInner.style[key] = style.inner[key] + unit;
}
let affixedEvent = 'affixed.'+ affixType.toLowerCase().replace('viewport-', '') + EVENT_KEY;
StickySidebar.eventTrigger(this.sidebar, affixedEvent);
} else {
if( this._initialized ) this.sidebarInner.style.left = style.inner.left;
}
this.affixedType = affixType;
}
/**
* Breakdown sticky sidebar when window width is below `options.minWidth` value.
* @protected
*/
_widthBreakpoint(){
if( window.innerWidth <= this.options.minWidth ){
this._breakpoint = true;
this.affixedType = 'STATIC';
this.sidebar.removeAttribute('style');
StickySidebar.removeClass(this.sidebar, this.options.stickyClass);
this.sidebarInner.removeAttribute('style');
} else {
this._breakpoint = false;
}
}
/**
* Switches between functions stack for each event type, if there's no
* event, it will re-initialize sticky sidebar.
* @public
*/
updateSticky(event = {}){
if( this._running ) return;
this._running = true;
((eventType) => {
requestAnimationFrame(() => {
switch( eventType ){
// When browser is scrolling and re-calculate just dimensions
// within scroll.
case 'scroll':
this._calcDimensionsWithScroll();
this.observeScrollDir();
this.stickyPosition();
break;
// When browser is resizing or there's no event, observe width
// breakpoint and re-calculate dimensions.
case 'resize':
default:
this._widthBreakpoint();
this.calcDimensions();
this.stickyPosition(true);
break;
}
this._running = false;
});
})(event.type);
}
/**
* Set browser support features to the public property.
* @private
*/
_setSupportFeatures(){
var support = this.support;
support.transform = StickySidebar.supportTransform();
support.transform3d = StickySidebar.supportTransform(true);
}
/**
* Get translate value, if the browser supports transfrom3d, it will adopt it.
* and the same with translate. if browser doesn't support both return false.
* @param {Number} y - Value of Y-axis.
* @param {Number} x - Value of X-axis.
* @param {Number} z - Value of Z-axis.
* @return {String|False}
*/
_getTranslate(y = 0, x = 0, z = 0){
if( this.support.transform3d ) return 'translate3d(' + y +', '+ x +', '+ z +')';
else if( this.support.translate ) return 'translate('+ y +', '+ x +')';
else return false;
}
/**
* Destroy sticky sidebar plugin.
* @public
*/
destroy(){
window.removeEventListener('resize', this, {capture: false});
window.removeEventListener('scroll', this, {capture: false});
this.sidebar.classList.remove(this.options.stickyClass);
this.sidebar.style.minHeight = '';
this.sidebar.removeEventListener('update' + EVENT_KEY, this);
var styleReset = {inner: {}, outer: {}};
styleReset.inner = {position: '', top: '', left: '', bottom: '', width: '', transform: ''};
styleReset.outer = {height: '', position: ''};
for( let key in styleReset.outer )
this.sidebar.style[key] = styleReset.outer[key];
for( let key in styleReset.inner )
this.sidebarInner.style[key] = styleReset.inner[key];
if( this.options.resizeSensor && 'undefined' !== typeof ResizeSensor ){
ResizeSensor.detach(this.sidebarInner, this.handleEvent);
ResizeSensor.detach(this.container, this.handleEvent);
}
}
/**
* Determine if the browser supports CSS transform feature.
* @function
* @static
* @param {Boolean} transform3d - Detect transform with translate3d.
* @return {String}
*/
static supportTransform(transform3d){
var result = false,
property = (transform3d) ? 'perspective' : 'transform',
upper = property.charAt(0).toUpperCase() + property.slice(1),
prefixes = ['Webkit', 'Moz', 'O', 'ms'],
support = document.createElement('support'),
style = support.style;
(property + ' ' + prefixes.join(upper + ' ') + upper).split(' ').forEach(function(property, i) {
if (style[property] !== undefined) {
result = property;
return false;
}
});
return result;
}
/**
* Trigger custom event.
* @static
* @param {DOMObject} element - Target element on the DOM.
* @param {String} eventName - Event name.
* @param {Object} data -
*/
static eventTrigger(element, eventName, data){
try{
var event = new CustomEvent(eventName, {detail: data});
} catch(e){
var event = document.createEvent('CustomEvent');
event.initCustomEvent(eventName, true, true, data);
}
element.dispatchEvent(event);
}
/**
* Extend options object with defaults.
* @function
* @static
*/
static extend(defaults, options){
var results = {};
for( let key in defaults ){
if( 'undefined' !== typeof options[key] ) results[key] = options[key];
else results[key] = defaults[key];
}
return results;
}
/**
* Get current coordinates left and top of specific element.
* @static
*/
static offsetRelative(element){
var result = {left: 0, top: 0};
do{
let offsetTop = element.offsetTop;
let offsetLeft = element.offsetLeft;
if( ! isNaN(offsetTop) )
result.top += offsetTop;
if( ! isNaN(offsetLeft) )
result.left += offsetLeft;
element = ( 'BODY' === element.tagName ) ?
element.parentElement : element.offsetParent;
} while(element)
return result;
}
/**
* Add specific class name to specific element.
* @static
* @param {ObjectDOM} element
* @param {String} className
*/
static addClass(element, className){
if( ! StickySidebar.hasClass(element, className) ){
if (element.classList)
element.classList.add(className);
else
element.className += ' ' + className;
}
}
/**
* Remove specific class name to specific element
* @static
* @param {ObjectDOM} element
* @param {String} className
*/
static removeClass(element, className){
if( StickySidebar.hasClass(element, className) ){
if (element.classList)
element.classList.remove(className);
else
element.className = element.className.replace(new RegExp('(^|\\b)' + className.split(' ').join('|') + '(\\b|$)', 'gi'), ' ');
}
}
/**
* Determine weather the element has specific class name.
* @static
* @param {ObjectDOM} element
* @param {String} className
*/
static hasClass(element, className){
if (element.classList)
return element.classList.contains(className);
else
return new RegExp('(^| )' + className + '( |$)', 'gi').test(element.className);
}
/**
* Gets default values of configuration options.
* @static
* @return {Object}
*/
static get defaults(){
return DEFAULTS;
}
}
return StickySidebar;
})();
// Global
// -------------------------
window.StickySidebar = StickySidebar;