\";\n var observer = new MutationObserver(function (mutations) {\n observer.disconnect();\n var mutation = mutations[0];\n\n if (mutation && mutation.type == \"childList\") {\n var removedNode = mutation.removedNodes[0];\n var isBuggy = removedNode.childNodes.length == 0;\n callback(isBuggy);\n }\n });\n observer.observe(element, {\n childList: true,\n subtree: true\n });\n element.innerHTML = \"\";\n }\n\n function patchInnerHTMLToRemoveChildNodes() {\n var _HTMLElement = HTMLElement,\n prototype = _HTMLElement.prototype;\n var descriptor = Object.getOwnPropertyDescriptor(prototype, \"innerHTML\");\n if (!descriptor) return;\n var _set = descriptor.set;\n if (!_set) return;\n Object.defineProperty(prototype, \"innerHTML\", {\n set: function set(value) {\n while (this.lastChild) {\n this.removeChild(this.lastChild);\n }\n\n _set.call(this, value);\n }\n });\n }\n})();","function _typeof(obj) { if (typeof Symbol === \"function\" && typeof Symbol.iterator === \"symbol\") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === \"function\" && obj.constructor === Symbol && obj !== Symbol.prototype ? \"symbol\" : typeof obj; }; } return _typeof(obj); }\n\n/**\n * Copyright 2016 Google Inc. All Rights Reserved.\n *\n * Licensed under the W3C SOFTWARE AND DOCUMENT NOTICE AND LICENSE.\n *\n * https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document\n *\n */\n(function () {\n 'use strict'; // Exit early if we're not running in a browser.\n\n if ((typeof window === \"undefined\" ? \"undefined\" : _typeof(window)) !== 'object') {\n return;\n } // Exit early if all IntersectionObserver and IntersectionObserverEntry\n // features are natively supported.\n\n\n if ('IntersectionObserver' in window && 'IntersectionObserverEntry' in window && 'intersectionRatio' in window.IntersectionObserverEntry.prototype) {\n // Minimal polyfill for Edge 15's lack of `isIntersecting`\n // See: https://github.com/w3c/IntersectionObserver/issues/211\n if (!('isIntersecting' in window.IntersectionObserverEntry.prototype)) {\n Object.defineProperty(window.IntersectionObserverEntry.prototype, 'isIntersecting', {\n get: function get() {\n return this.intersectionRatio > 0;\n }\n });\n }\n\n return;\n }\n /**\n * A local reference to the document.\n */\n\n\n var document = window.document;\n /**\n * An IntersectionObserver registry. This registry exists to hold a strong\n * reference to IntersectionObserver instances currently observing a target\n * element. Without this registry, instances without another reference may be\n * garbage collected.\n */\n\n var registry = [];\n /**\n * Creates the global IntersectionObserverEntry constructor.\n * https://w3c.github.io/IntersectionObserver/#intersection-observer-entry\n * @param {Object} entry A dictionary of instance properties.\n * @constructor\n */\n\n function IntersectionObserverEntry(entry) {\n this.time = entry.time;\n this.target = entry.target;\n this.rootBounds = entry.rootBounds;\n this.boundingClientRect = entry.boundingClientRect;\n this.intersectionRect = entry.intersectionRect || getEmptyRect();\n this.isIntersecting = !!entry.intersectionRect; // Calculates the intersection ratio.\n\n var targetRect = this.boundingClientRect;\n var targetArea = targetRect.width * targetRect.height;\n var intersectionRect = this.intersectionRect;\n var intersectionArea = intersectionRect.width * intersectionRect.height; // Sets intersection ratio.\n\n if (targetArea) {\n // Round the intersection ratio to avoid floating point math issues:\n // https://github.com/w3c/IntersectionObserver/issues/324\n this.intersectionRatio = Number((intersectionArea / targetArea).toFixed(4));\n } else {\n // If area is zero and is intersecting, sets to 1, otherwise to 0\n this.intersectionRatio = this.isIntersecting ? 1 : 0;\n }\n }\n /**\n * Creates the global IntersectionObserver constructor.\n * https://w3c.github.io/IntersectionObserver/#intersection-observer-interface\n * @param {Function} callback The function to be invoked after intersection\n * changes have queued. The function is not invoked if the queue has\n * been emptied by calling the `takeRecords` method.\n * @param {Object=} opt_options Optional configuration options.\n * @constructor\n */\n\n\n function IntersectionObserver(callback, opt_options) {\n var options = opt_options || {};\n\n if (typeof callback != 'function') {\n throw new Error('callback must be a function');\n }\n\n if (options.root && options.root.nodeType != 1) {\n throw new Error('root must be an Element');\n } // Binds and throttles `this._checkForIntersections`.\n\n\n this._checkForIntersections = throttle(this._checkForIntersections.bind(this), this.THROTTLE_TIMEOUT); // Private properties.\n\n this._callback = callback;\n this._observationTargets = [];\n this._queuedEntries = [];\n this._rootMarginValues = this._parseRootMargin(options.rootMargin); // Public properties.\n\n this.thresholds = this._initThresholds(options.threshold);\n this.root = options.root || null;\n this.rootMargin = this._rootMarginValues.map(function (margin) {\n return margin.value + margin.unit;\n }).join(' ');\n }\n /**\n * The minimum interval within which the document will be checked for\n * intersection changes.\n */\n\n\n IntersectionObserver.prototype.THROTTLE_TIMEOUT = 100;\n /**\n * The frequency in which the polyfill polls for intersection changes.\n * this can be updated on a per instance basis and must be set prior to\n * calling `observe` on the first target.\n */\n\n IntersectionObserver.prototype.POLL_INTERVAL = null;\n /**\n * Use a mutation observer on the root element\n * to detect intersection changes.\n */\n\n IntersectionObserver.prototype.USE_MUTATION_OBSERVER = true;\n /**\n * Starts observing a target element for intersection changes based on\n * the thresholds values.\n * @param {Element} target The DOM element to observe.\n */\n\n IntersectionObserver.prototype.observe = function (target) {\n var isTargetAlreadyObserved = this._observationTargets.some(function (item) {\n return item.element == target;\n });\n\n if (isTargetAlreadyObserved) {\n return;\n }\n\n if (!(target && target.nodeType == 1)) {\n throw new Error('target must be an Element');\n }\n\n this._registerInstance();\n\n this._observationTargets.push({\n element: target,\n entry: null\n });\n\n this._monitorIntersections();\n\n this._checkForIntersections();\n };\n /**\n * Stops observing a target element for intersection changes.\n * @param {Element} target The DOM element to observe.\n */\n\n\n IntersectionObserver.prototype.unobserve = function (target) {\n this._observationTargets = this._observationTargets.filter(function (item) {\n return item.element != target;\n });\n\n if (!this._observationTargets.length) {\n this._unmonitorIntersections();\n\n this._unregisterInstance();\n }\n };\n /**\n * Stops observing all target elements for intersection changes.\n */\n\n\n IntersectionObserver.prototype.disconnect = function () {\n this._observationTargets = [];\n\n this._unmonitorIntersections();\n\n this._unregisterInstance();\n };\n /**\n * Returns any queue entries that have not yet been reported to the\n * callback and clears the queue. This can be used in conjunction with the\n * callback to obtain the absolute most up-to-date intersection information.\n * @return {Array} The currently queued entries.\n */\n\n\n IntersectionObserver.prototype.takeRecords = function () {\n var records = this._queuedEntries.slice();\n\n this._queuedEntries = [];\n return records;\n };\n /**\n * Accepts the threshold value from the user configuration object and\n * returns a sorted array of unique threshold values. If a value is not\n * between 0 and 1 and error is thrown.\n * @private\n * @param {Array|number=} opt_threshold An optional threshold value or\n * a list of threshold values, defaulting to [0].\n * @return {Array} A sorted list of unique and valid threshold values.\n */\n\n\n IntersectionObserver.prototype._initThresholds = function (opt_threshold) {\n var threshold = opt_threshold || [0];\n if (!Array.isArray(threshold)) threshold = [threshold];\n return threshold.sort().filter(function (t, i, a) {\n if (typeof t != 'number' || isNaN(t) || t < 0 || t > 1) {\n throw new Error('threshold must be a number between 0 and 1 inclusively');\n }\n\n return t !== a[i - 1];\n });\n };\n /**\n * Accepts the rootMargin value from the user configuration object\n * and returns an array of the four margin values as an object containing\n * the value and unit properties. If any of the values are not properly\n * formatted or use a unit other than px or %, and error is thrown.\n * @private\n * @param {string=} opt_rootMargin An optional rootMargin value,\n * defaulting to '0px'.\n * @return {Array