(function (global, factory) { typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() : typeof define === 'function' && define.amd ? define(factory) : (global.stickybits = factory()); }(this, (function () { 'use strict'; /* STICKYBITS 💉 -------- > a lightweight alternative to `position: sticky` polyfills 🍬 -------- - each method is documented above it our view the readme - Stickybits does not manage polymorphic functionality (position like properties) * polymorphic functionality: (in the context of describing Stickybits) means making things like `position: sticky` be loosely supported with position fixed. It also means that features like `useStickyClasses` takes on styles like `position: fixed`. -------- defaults 🔌 -------- - version = `package.json` version - userAgent = viewer browser agent - target = DOM element selector - noStyles = boolean - offset = number - parentClass = 'string' - scrollEl = window || DOM element selector - stickyClass = 'string' - stuckClass = 'string' - useStickyClasses = boolean - verticalPosition = 'string' -------- props🔌 -------- - p = props {object} -------- instance note -------- - stickybits parent methods return this - stickybits instance methods return an instance item -------- nomenclature -------- - target => el => e - props => o || p - instance => item => it -------- methods -------- - .definePosition = defines sticky or fixed - .addInstance = an array of objects for each Stickybits Target - .getClosestParent = gets the parent for non-window scroll - .computeScrollOffsets = computes scroll position - .toggleClasses = older browser toggler - .manageState = manages sticky state - .removeClass = older browser support class remover - .removeInstance = removes an instance - .cleanup = removes all Stickybits instances and cleans up dom from stickybits */ function Stickybits(target, obj) { var o = typeof obj !== 'undefined' ? obj : {}; this.version = '2.0.13'; this.userAgent = window.navigator.userAgent || 'no `userAgent` provided by the browser'; this.props = { noStyles: o.noStyles || false, stickyBitStickyOffset: o.stickyBitStickyOffset || 0, parentClass: o.parentClass || 'js-stickybit-parent', scrollEl: o.scrollEl || window, stickyClass: o.stickyClass || 'js-is-sticky', stuckClass: o.stuckClass || 'js-is-stuck', useStickyClasses: o.useStickyClasses || false, verticalPosition: o.verticalPosition || 'top' }; var p = this.props; /* define positionVal ---- - uses a computed (`.definePosition()`) - defined the position */ p.positionVal = this.definePosition() || 'fixed'; var vp = p.verticalPosition; var ns = p.noStyles; var pv = p.positionVal; this.els = typeof target === 'string' ? document.querySelectorAll(target) : target; if (!('length' in this.els)) this.els = [this.els]; this.instances = []; for (var i = 0; i < this.els.length; i += 1) { var el = this.els[i]; var styles = el.style; if (vp === 'top' && !ns) styles[vp] = p.stickyBitStickyOffset + 'px'; if (pv !== 'fixed' && p.useStickyClasses === false) { styles.position = pv; } else { // const stickyManager = new ManageSticky(el, p) if (pv !== 'fixed') styles.position = pv; var instance = this.addInstance(el, p); // instances are an array of objects this.instances.push(instance); } } return this; } /* setStickyPosition ✔️ -------- — most basic thing stickybits does => checks to see if position sticky is supported => defined the position to be used => stickybits works accordingly */ Stickybits.prototype.definePosition = function () { var prefix = ['', '-o-', '-webkit-', '-moz-', '-ms-']; var test = document.head.style; for (var i = 0; i < prefix.length; i += 1) { test.position = prefix[i] + 'sticky'; } var stickyProp = 'fixed'; if (typeof test.position !== 'undefined') stickyProp = test.position; test.position = ''; return stickyProp; }; /* addInstance ✔️ -------- — manages instances of items - takes in an el and props - returns an item object --- - target = el - o = {object} = props - scrollEl = 'string' - verticalPosition = number - off = boolean - parentClass = 'string' - stickyClass = 'string' - stuckClass = 'string' --- - defined later - parent = dom element - state = 'string' - offset = number - stickyStart = number - stickyStop = number - returns an instance object */ Stickybits.prototype.addInstance = function addInstance(el, props) { var _this = this; var item = { el: el, parent: el.parentNode, props: props }; var p = item.props; item.parent.className += ' ' + props.parentClass; var se = p.scrollEl; item.isWin = se === window; if (!item.isWin) se = this.getClosestParent(item.el, se); this.computeScrollOffsets(item); item.state = 'default'; item.stateContainer = function () { _this.manageState(item); }; se.addEventListener('scroll', item.stateContainer); return item; }; /* -------- getParent 👨‍ -------- - a helper function that gets the target element's parent selected el - only used for non `window` scroll elements - supports older browsers */ Stickybits.prototype.getClosestParent = function getClosestParent(el, matchSelector) { // p = parent element var p = document.querySelector(matchSelector); var e = el; if (e.parentElement === p) return p; // traverse up the dom tree until we get to the parent while (e.parentElement !== p) { e = e.parentElement; } // return parent element return p; }; /* computeScrollOffsets 📊 --- computeScrollOffsets for Stickybits - defines - offset - start - stop */ Stickybits.prototype.computeScrollOffsets = function computeScrollOffsets(item) { var it = item; var p = it.props; var parent = it.parent; var iw = it.isWin; var scrollElOffset = 0; var stickyStart = parent.getBoundingClientRect().top; if (!iw && p.positionVal === 'fixed') { scrollElOffset = p.scrollEl.getBoundingClientRect().top; stickyStart = parent.getBoundingClientRect().top - scrollElOffset; } it.offset = scrollElOffset + p.stickyBitStickyOffset; it.stickyStart = stickyStart - it.offset; it.stickyStop = stickyStart + parent.offsetHeight - (it.el.offsetHeight + it.offset); return it; }; /* toggleClasses ⚖️ --- toggles classes (for older browser support) r = removed class a = added class */ Stickybits.prototype.toggleClasses = function toggleClasses(el, r, a) { var e = el; var cArray = e.className.split(' '); if (a && cArray.indexOf(a) === -1) cArray.push(a); var rItem = cArray.indexOf(r); if (rItem !== -1) cArray.splice(rItem, 1); e.className = cArray.join(' '); }; /* manageState 📝 --- - defines the state - normal - sticky - stuck */ Stickybits.prototype.manageState = function manageState(item) { // cache object var it = item; var e = it.el; var p = it.props; var state = it.state; var start = it.stickyStart; var stop = it.stickyStop; var stl = e.style; // cache props var ns = p.noStyles; var pv = p.positionVal; var se = p.scrollEl; var sticky = p.stickyClass; var stuck = p.stuckClass; var vp = p.verticalPosition; /* requestAnimationFrame --- - use rAF - or stub rAF */ var rAF = se.requestAnimationFrame; if (!it.isWin || typeof rAF === 'undefined') { rAF = function rAFDummy(f) { f(); }; } /* define scroll vars --- - scroll - notSticky - isSticky - isStuck */ var tC = this.toggleClasses; var scroll = it.isWin ? se.scrollY || se.pageYOffset : se.scrollTop; var notSticky = scroll > start && scroll < stop && (state === 'default' || state === 'stuck'); var isSticky = scroll <= start && state === 'sticky'; var isStuck = scroll >= stop && state === 'sticky'; /* Unnamed arrow functions within this block --- - help wanted or discussion - view test.stickybits.js - `stickybits .manageState `position: fixed` interface` for more awareness 👀 */ if (notSticky) { it.state = 'sticky'; rAF(function () { tC(e, stuck, sticky); stl.position = pv; if (ns) return; stl.bottom = ''; stl[vp] = p.stickyBitStickyOffset + 'px'; }); } else if (isSticky) { it.state = 'default'; rAF(function () { tC(e, sticky); if (pv === 'fixed') stl.position = ''; }); } else if (isStuck) { it.state = 'stuck'; rAF(function () { tC(e, sticky, stuck); if (pv !== 'fixed' || ns) return; stl.top = ''; stl.bottom = '0'; stl.position = 'absolute'; }); } return it; }; /* removes an instance 👋 -------- - cleanup instance */ Stickybits.prototype.removeInstance = function removeInstance(instance) { var e = instance.el; var p = instance.props; var tC = this.toggleClasses; e.style.position = ''; e.style[p.verticalPosition] = ''; tC(e, p.stickyClass); tC(e, p.stuckClass); tC(e.parentNode, p.parentClass); }; /* cleanup 🛁 -------- - cleans up each instance - clears instance */ Stickybits.prototype.cleanup = function cleanup() { for (var i = 0; i < this.instances.length; i += 1) { var instance = this.instances[i]; instance.props.scrollEl.removeEventListener('scroll', instance.stateContainer); this.removeInstance(instance); } this.manageState = false; this.instances = []; }; /* export -------- exports StickBits to be used 🏁 */ function stickybits(target, o) { return new Stickybits(target, o); } return stickybits; }))); var stickybit = stickybits('#aside', {useStickyClasses: true, scrollEl: '#main'});