492 lines
14 KiB
JavaScript
Executable File
492 lines
14 KiB
JavaScript
Executable File
/*!
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* Stickyfill – `position: sticky` polyfill
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* v. 2.0.2 | https://github.com/wilddeer/stickyfill
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* MIT License
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*/
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'use strict';
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/*
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* 1. Check if the browser supports `position: sticky` natively or is too old to run the polyfill.
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* If either of these is the case set `seppuku` flag. It will be checked later to disable key features
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* of the polyfill, but the API will remain functional to avoid breaking things.
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*/
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let seppuku = false;
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// The polyfill cant’t function properly without `getComputedStyle`.
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if (!window.getComputedStyle) seppuku = true;
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// Dont’t get in a way if the browser supports `position: sticky` natively.
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else {
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const testNode = document.createElement('div');
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if (
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['', '-webkit-', '-moz-', '-ms-'].some(prefix => {
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try {
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testNode.style.position = prefix + 'sticky';
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}
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catch(e) {}
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return testNode.style.position != '';
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})
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) seppuku = true;
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}
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/*
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* 2. “Global” vars used across the polyfill
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*/
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// Check if Shadow Root constructor exists to make further checks simpler
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const shadowRootExists = typeof ShadowRoot !== 'undefined';
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// Last saved scroll position
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const scroll = {
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top: null,
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left: null
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};
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// Array of created Sticky instances
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const stickies = [];
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/*
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* 3. Utility functions
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*/
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function extend (targetObj, sourceObject) {
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for (var key in sourceObject) {
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if (sourceObject.hasOwnProperty(key)) {
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targetObj[key] = sourceObject[key];
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}
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}
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}
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function parseNumeric (val) {
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return parseFloat(val) || 0;
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}
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function getDocOffsetTop (node) {
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let docOffsetTop = 0;
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while (node) {
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docOffsetTop += node.offsetTop;
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node = node.offsetParent;
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}
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return docOffsetTop;
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}
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/*
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* 4. Sticky class
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*/
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class Sticky {
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constructor (node) {
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if (!(node instanceof HTMLElement))
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throw new Error('First argument must be HTMLElement');
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if (stickies.some(sticky => sticky._node === node))
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throw new Error('Stickyfill is already applied to this node');
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this._node = node;
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this._stickyMode = null;
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this._active = false;
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stickies.push(this);
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this.refresh();
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}
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refresh () {
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if (seppuku || this._removed) return;
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if (this._active) this._deactivate();
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const node = this._node;
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/*
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* 1. Check if the node can be activated
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*/
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const nodeComputedStyle = getComputedStyle(node);
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if (
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isNaN(parseFloat(nodeComputedStyle.top)) ||
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nodeComputedStyle.display == 'table-cell' ||
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nodeComputedStyle.display == 'none'
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) return;
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this._active = true;
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/*
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* 2. Get necessary node parameters
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*/
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const referenceNode = node.parentNode;
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const parentNode = shadowRootExists && referenceNode instanceof ShadowRoot? referenceNode.host: referenceNode;
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const nodeWinOffset = node.getBoundingClientRect();
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const parentWinOffset = parentNode.getBoundingClientRect();
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const parentComputedStyle = getComputedStyle(parentNode);
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this._parent = {
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node: parentNode,
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styles: {
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position: parentNode.style.position
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},
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offsetHeight: parentNode.offsetHeight
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};
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this._offsetToWindow = {
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left: nodeWinOffset.left,
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right: document.documentElement.clientWidth - nodeWinOffset.right
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};
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this._offsetToParent = {
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top: nodeWinOffset.top - parentWinOffset.top - parseNumeric(parentComputedStyle.borderTopWidth),
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left: nodeWinOffset.left - parentWinOffset.left - parseNumeric(parentComputedStyle.borderLeftWidth),
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right: -nodeWinOffset.right + parentWinOffset.right - parseNumeric(parentComputedStyle.borderRightWidth)
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};
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this._styles = {
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position: node.style.position,
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top: node.style.top,
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bottom: node.style.bottom,
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left: node.style.left,
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right: node.style.right,
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width: node.style.width,
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marginTop: node.style.marginTop,
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marginLeft: node.style.marginLeft,
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marginRight: node.style.marginRight
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};
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const nodeTopValue = parseNumeric(nodeComputedStyle.top);
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this._limits = {
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start: nodeWinOffset.top + window.pageYOffset - nodeTopValue,
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end: parentWinOffset.top + window.pageYOffset + parentNode.offsetHeight -
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parseNumeric(parentComputedStyle.borderBottomWidth) - node.offsetHeight -
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nodeTopValue - parseNumeric(nodeComputedStyle.marginBottom)
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};
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/*
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* 3. Ensure that the node will be positioned relatively to the parent node
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*/
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const parentPosition = parentComputedStyle.position;
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if (
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parentPosition != 'absolute' &&
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parentPosition != 'relative'
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) {
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parentNode.style.position = 'relative';
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}
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/*
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* 4. Create a clone
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*/
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const clone = this._clone = {};
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clone.node = document.createElement('div');
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// Apply styles to the clone
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extend(clone.node.style, {
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width: nodeWinOffset.right - nodeWinOffset.left + 'px',
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height: nodeWinOffset.bottom - nodeWinOffset.top + 'px',
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marginTop: nodeComputedStyle.marginTop,
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marginBottom: nodeComputedStyle.marginBottom,
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marginLeft: nodeComputedStyle.marginLeft,
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marginRight: nodeComputedStyle.marginRight,
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cssFloat: nodeComputedStyle.cssFloat,
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padding: 0,
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border: 0,
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borderSpacing: 0,
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fontSize: '1em',
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position: 'static'
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});
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referenceNode.insertBefore(clone.node, node);
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clone.docOffsetTop = getDocOffsetTop(clone.node);
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this._recalcPosition();
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}
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_recalcPosition () {
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if (!this._active || this._removed) return;
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const stickyMode = scroll.top <= this._limits.start? 'start': scroll.top >= this._limits.end? 'end': 'middle';
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if (this._stickyMode == stickyMode) return;
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switch (stickyMode) {
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case 'start':
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extend(this._node.style, {
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position: 'absolute',
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left: this._offsetToParent.left + 'px',
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right: this._offsetToParent.right + 'px',
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top: this._offsetToParent.top + 'px',
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bottom: 'auto',
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width: 'auto',
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marginLeft: 0,
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marginRight: 0,
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marginTop: 0
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});
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break;
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case 'middle':
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extend(this._node.style, {
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position: 'fixed',
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left: this._offsetToWindow.left + 'px',
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right: this._offsetToWindow.right + 'px',
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top: this._styles.top,
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bottom: 'auto',
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width: 'auto',
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marginLeft: 0,
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marginRight: 0,
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marginTop: 0
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});
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break;
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case 'end':
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extend(this._node.style, {
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position: 'absolute',
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left: this._offsetToParent.left + 'px',
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right: this._offsetToParent.right + 'px',
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top: 'auto',
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bottom: 0,
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width: 'auto',
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marginLeft: 0,
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marginRight: 0
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});
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break;
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}
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this._stickyMode = stickyMode;
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}
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_fastCheck () {
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if (!this._active || this._removed) return;
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if (
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Math.abs(getDocOffsetTop(this._clone.node) - this._clone.docOffsetTop) > 1 ||
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Math.abs(this._parent.node.offsetHeight - this._parent.offsetHeight) > 1
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) this.refresh();
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}
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_deactivate () {
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if (!this._active || this._removed) return;
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this._clone.node.parentNode.removeChild(this._clone.node);
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delete this._clone;
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extend(this._node.style, this._styles);
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delete this._styles;
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// Check whether element’s parent node is used by other stickies.
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// If not, restore parent node’s styles.
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if (!stickies.some(sticky => sticky !== this && sticky._parent && sticky._parent.node === this._parent.node)) {
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extend(this._parent.node.style, this._parent.styles);
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}
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delete this._parent;
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this._stickyMode = null;
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this._active = false;
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delete this._offsetToWindow;
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delete this._offsetToParent;
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delete this._limits;
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}
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remove () {
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this._deactivate();
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stickies.some((sticky, index) => {
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if (sticky._node === this._node) {
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stickies.splice(index, 1);
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return true;
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}
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});
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this._removed = true;
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}
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}
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/*
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* 5. Stickyfill API
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*/
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const Stickyfill = {
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stickies,
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Sticky,
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addOne (node) {
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// Check whether it’s a node
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if (!(node instanceof HTMLElement)) {
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// Maybe it’s a node list of some sort?
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// Take first node from the list then
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if (node.length && node[0]) node = node[0];
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else return;
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}
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// Check if Stickyfill is already applied to the node
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// and return existing sticky
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for (var i = 0; i < stickies.length; i++) {
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if (stickies[i]._node === node) return stickies[i];
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}
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// Create and return new sticky
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return new Sticky(node);
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},
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add (nodeList) {
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// If it’s a node make an array of one node
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if (nodeList instanceof HTMLElement) nodeList = [nodeList];
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// Check if the argument is an iterable of some sort
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if (!nodeList.length) return;
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// Add every element as a sticky and return an array of created Sticky instances
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const addedStickies = [];
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for (let i = 0; i < nodeList.length; i++) {
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const node = nodeList[i];
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// If it’s not an HTMLElement – create an empty element to preserve 1-to-1
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// correlation with input list
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if (!(node instanceof HTMLElement)) {
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addedStickies.push(void 0);
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continue;
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}
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// If Stickyfill is already applied to the node
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// add existing sticky
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if (stickies.some(sticky => {
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if (sticky._node === node) {
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addedStickies.push(sticky);
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return true;
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}
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})) continue;
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// Create and add new sticky
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addedStickies.push(new Sticky(node));
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}
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return addedStickies;
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},
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refreshAll () {
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stickies.forEach(sticky => sticky.refresh());
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},
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removeOne (node) {
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// Check whether it’s a node
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if (!(node instanceof HTMLElement)) {
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// Maybe it’s a node list of some sort?
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// Take first node from the list then
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if (node.length && node[0]) node = node[0];
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else return;
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}
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// Remove the stickies bound to the nodes in the list
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stickies.some(sticky => {
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if (sticky._node === node) {
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sticky.remove();
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return true;
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}
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});
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},
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remove (nodeList) {
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// If it’s a node make an array of one node
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if (nodeList instanceof HTMLElement) nodeList = [nodeList];
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// Check if the argument is an iterable of some sort
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if (!nodeList.length) return;
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// Remove the stickies bound to the nodes in the list
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for (let i = 0; i < nodeList.length; i++) {
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const node = nodeList[i];
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stickies.some(sticky => {
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if (sticky._node === node) {
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sticky.remove();
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return true;
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}
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});
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}
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},
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removeAll () {
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while (stickies.length) stickies[0].remove();
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}
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};
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/*
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* 6. Setup events (unless the polyfill was disabled)
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*/
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function init () {
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// Watch for scroll position changes and trigger recalc/refresh if needed
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function checkScroll () {
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if (window.pageXOffset != scroll.left) {
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scroll.top = window.pageYOffset;
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scroll.left = window.pageXOffset;
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Stickyfill.refreshAll();
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}
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else if (window.pageYOffset != scroll.top) {
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scroll.top = window.pageYOffset;
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scroll.left = window.pageXOffset;
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// recalc position for all stickies
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stickies.forEach(sticky => sticky._recalcPosition());
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}
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}
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checkScroll();
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window.addEventListener('scroll', checkScroll);
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// Watch for window resizes and device orientation cahnges and trigger refresh
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window.addEventListener('resize', Stickyfill.refreshAll);
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window.addEventListener('orientationchange', Stickyfill.refreshAll);
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//Fast dirty check for layout changes every 500ms
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let fastCheckTimer;
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function startFastCheckTimer () {
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fastCheckTimer = setInterval(function () {
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stickies.forEach(sticky => sticky._fastCheck());
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}, 500);
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}
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function stopFastCheckTimer () {
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clearInterval(fastCheckTimer);
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}
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let docHiddenKey;
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let visibilityChangeEventName;
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if ('hidden' in document) {
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docHiddenKey = 'hidden';
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visibilityChangeEventName = 'visibilitychange';
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}
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else if ('webkitHidden' in document) {
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docHiddenKey = 'webkitHidden';
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visibilityChangeEventName = 'webkitvisibilitychange';
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}
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if (visibilityChangeEventName) {
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if (!document[docHiddenKey]) startFastCheckTimer();
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document.addEventListener(visibilityChangeEventName, () => {
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if (document[docHiddenKey]) {
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stopFastCheckTimer();
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}
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else {
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startFastCheckTimer();
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}
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});
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}
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else startFastCheckTimer();
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}
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if (!seppuku) init();
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/*
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* 7. Expose Stickyfill
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*/
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if (typeof module != 'undefined' && module.exports) {
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module.exports = Stickyfill;
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}
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else {
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window.Stickyfill = Stickyfill;
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}
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