712 lines
23 KiB
JavaScript
712 lines
23 KiB
JavaScript
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/**
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* Copyright 2016 Google Inc. All Rights Reserved.
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*
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* Licensed under the W3C SOFTWARE AND DOCUMENT NOTICE AND LICENSE.
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*
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* https://www.w3.org/Consortium/Legal/2015/copyright-software-and-document
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*
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*/
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;(function(window, document) {
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'use strict'
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// Exits early if all IntersectionObserver and IntersectionObserverEntry
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// features are natively supported.
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if (
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'IntersectionObserver' in window &&
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'IntersectionObserverEntry' in window &&
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'intersectionRatio' in window.IntersectionObserverEntry.prototype
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) {
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// Minimal polyfill for Edge 15's lack of `isIntersecting`
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// See: https://github.com/w3c/IntersectionObserver/issues/211
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if (!('isIntersecting' in window.IntersectionObserverEntry.prototype)) {
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Object.defineProperty(
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window.IntersectionObserverEntry.prototype,
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'isIntersecting',
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{
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get: function() {
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return this.intersectionRatio > 0
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}
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}
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)
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}
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return
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}
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/**
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* An IntersectionObserver registry. This registry exists to hold a strong
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* reference to IntersectionObserver instances currently observering a target
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* element. Without this registry, instances without another reference may be
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* garbage collected.
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*/
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var registry = []
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/**
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* Creates the global IntersectionObserverEntry constructor.
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* https://w3c.github.io/IntersectionObserver/#intersection-observer-entry
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* @param {Object} entry A dictionary of instance properties.
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* @constructor
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*/
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function IntersectionObserverEntry(entry) {
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this.time = entry.time
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this.target = entry.target
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this.rootBounds = entry.rootBounds
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this.boundingClientRect = entry.boundingClientRect
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this.intersectionRect = entry.intersectionRect || getEmptyRect()
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this.isIntersecting = !!entry.intersectionRect
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// Calculates the intersection ratio.
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var targetRect = this.boundingClientRect
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var targetArea = targetRect.width * targetRect.height
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var intersectionRect = this.intersectionRect
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var intersectionArea = intersectionRect.width * intersectionRect.height
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// Sets intersection ratio.
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if (targetArea) {
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this.intersectionRatio = intersectionArea / targetArea
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} else {
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// If area is zero and is intersecting, sets to 1, otherwise to 0
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this.intersectionRatio = this.isIntersecting ? 1 : 0
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}
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}
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/**
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* Creates the global IntersectionObserver constructor.
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* https://w3c.github.io/IntersectionObserver/#intersection-observer-interface
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* @param {Function} callback The function to be invoked after intersection
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* changes have queued. The function is not invoked if the queue has
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* been emptied by calling the `takeRecords` method.
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* @param {Object=} opt_options Optional configuration options.
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* @constructor
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*/
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function IntersectionObserver(callback, opt_options) {
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var options = opt_options || {}
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if (typeof callback != 'function') {
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throw new Error('callback must be a function')
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}
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if (options.root && options.root.nodeType != 1) {
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throw new Error('root must be an Element')
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}
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// Binds and throttles `this._checkForIntersections`.
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this._checkForIntersections = throttle(
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this._checkForIntersections.bind(this),
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this.THROTTLE_TIMEOUT
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)
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// Private properties.
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this._callback = callback
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this._observationTargets = []
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this._queuedEntries = []
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this._rootMarginValues = this._parseRootMargin(options.rootMargin)
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// Public properties.
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this.thresholds = this._initThresholds(options.threshold)
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this.root = options.root || null
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this.rootMargin = this._rootMarginValues
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.map(function(margin) {
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return margin.value + margin.unit
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})
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.join(' ')
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}
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/**
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* The minimum interval within which the document will be checked for
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* intersection changes.
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*/
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IntersectionObserver.prototype.THROTTLE_TIMEOUT = 100
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/**
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* The frequency in which the polyfill polls for intersection changes.
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* this can be updated on a per instance basis and must be set prior to
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* calling `observe` on the first target.
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*/
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IntersectionObserver.prototype.POLL_INTERVAL = null
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/**
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* Use a mutation observer on the root element
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* to detect intersection changes.
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*/
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IntersectionObserver.prototype.USE_MUTATION_OBSERVER = true
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/**
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* Starts observing a target element for intersection changes based on
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* the thresholds values.
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* @param {Element} target The DOM element to observe.
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*/
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IntersectionObserver.prototype.observe = function(target) {
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var isTargetAlreadyObserved = this._observationTargets.some(function(item) {
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return item.element == target
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})
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if (isTargetAlreadyObserved) {
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return
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}
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if (!(target && target.nodeType == 1)) {
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throw new Error('target must be an Element')
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}
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this._registerInstance()
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this._observationTargets.push({ element: target, entry: null })
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this._monitorIntersections()
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this._checkForIntersections()
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}
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/**
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* Stops observing a target element for intersection changes.
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* @param {Element} target The DOM element to observe.
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*/
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IntersectionObserver.prototype.unobserve = function(target) {
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this._observationTargets = this._observationTargets.filter(function(item) {
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return item.element != target
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})
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if (!this._observationTargets.length) {
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this._unmonitorIntersections()
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this._unregisterInstance()
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}
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}
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/**
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* Stops observing all target elements for intersection changes.
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*/
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IntersectionObserver.prototype.disconnect = function() {
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this._observationTargets = []
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this._unmonitorIntersections()
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this._unregisterInstance()
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}
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/**
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* Returns any queue entries that have not yet been reported to the
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* callback and clears the queue. This can be used in conjunction with the
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* callback to obtain the absolute most up-to-date intersection information.
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* @return {Array} The currently queued entries.
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*/
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IntersectionObserver.prototype.takeRecords = function() {
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var records = this._queuedEntries.slice()
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this._queuedEntries = []
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return records
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}
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/**
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* Accepts the threshold value from the user configuration object and
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* returns a sorted array of unique threshold values. If a value is not
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* between 0 and 1 and error is thrown.
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* @private
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* @param {Array|number=} opt_threshold An optional threshold value or
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* a list of threshold values, defaulting to [0].
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* @return {Array} A sorted list of unique and valid threshold values.
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*/
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IntersectionObserver.prototype._initThresholds = function(opt_threshold) {
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var threshold = opt_threshold || [0]
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if (!Array.isArray(threshold)) threshold = [threshold]
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return threshold.sort().filter(function(t, i, a) {
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if (typeof t != 'number' || isNaN(t) || t < 0 || t > 1) {
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throw new Error(
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'threshold must be a number between 0 and 1 inclusively'
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)
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}
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return t !== a[i - 1]
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})
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}
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/**
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* Accepts the rootMargin value from the user configuration object
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* and returns an array of the four margin values as an object containing
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* the value and unit properties. If any of the values are not properly
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* formatted or use a unit other than px or %, and error is thrown.
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* @private
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* @param {string=} opt_rootMargin An optional rootMargin value,
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* defaulting to '0px'.
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* @return {Array<Object>} An array of margin objects with the keys
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* value and unit.
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*/
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IntersectionObserver.prototype._parseRootMargin = function(opt_rootMargin) {
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var marginString = opt_rootMargin || '0px'
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var margins = marginString.split(/\s+/).map(function(margin) {
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var parts = /^(-?\d*\.?\d+)(px|%)$/.exec(margin)
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if (!parts) {
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throw new Error('rootMargin must be specified in pixels or percent')
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}
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return { value: parseFloat(parts[1]), unit: parts[2] }
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})
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// Handles shorthand.
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margins[1] = margins[1] || margins[0]
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margins[2] = margins[2] || margins[0]
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margins[3] = margins[3] || margins[1]
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return margins
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}
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/**
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* Starts polling for intersection changes if the polling is not already
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* happening, and if the page's visibilty state is visible.
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* @private
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*/
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IntersectionObserver.prototype._monitorIntersections = function() {
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if (!this._monitoringIntersections) {
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this._monitoringIntersections = true
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// If a poll interval is set, use polling instead of listening to
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// resize and scroll events or DOM mutations.
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if (this.POLL_INTERVAL) {
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this._monitoringInterval = setInterval(
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this._checkForIntersections,
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this.POLL_INTERVAL
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)
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} else {
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addEvent(window, 'resize', this._checkForIntersections, true)
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addEvent(document, 'scroll', this._checkForIntersections, true)
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if (this.USE_MUTATION_OBSERVER && 'MutationObserver' in window) {
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this._domObserver = new MutationObserver(this._checkForIntersections)
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this._domObserver.observe(document, {
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attributes: true,
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childList: true,
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characterData: true,
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subtree: true
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})
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}
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}
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}
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}
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/**
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* Stops polling for intersection changes.
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* @private
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*/
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IntersectionObserver.prototype._unmonitorIntersections = function() {
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if (this._monitoringIntersections) {
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this._monitoringIntersections = false
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clearInterval(this._monitoringInterval)
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this._monitoringInterval = null
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removeEvent(window, 'resize', this._checkForIntersections, true)
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removeEvent(document, 'scroll', this._checkForIntersections, true)
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if (this._domObserver) {
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this._domObserver.disconnect()
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this._domObserver = null
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}
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}
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}
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/**
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* Scans each observation target for intersection changes and adds them
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* to the internal entries queue. If new entries are found, it
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* schedules the callback to be invoked.
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* @private
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*/
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IntersectionObserver.prototype._checkForIntersections = function() {
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var rootIsInDom = this._rootIsInDom()
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var rootRect = rootIsInDom ? this._getRootRect() : getEmptyRect()
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this._observationTargets.forEach(function(item) {
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var target = item.element
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var targetRect = getBoundingClientRect(target)
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var rootContainsTarget = this._rootContainsTarget(target)
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var oldEntry = item.entry
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var intersectionRect =
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rootIsInDom &&
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rootContainsTarget &&
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this._computeTargetAndRootIntersection(target, rootRect)
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var newEntry = (item.entry = new IntersectionObserverEntry({
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time: now(),
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target: target,
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boundingClientRect: targetRect,
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rootBounds: rootRect,
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intersectionRect: intersectionRect
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}))
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if (!oldEntry) {
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this._queuedEntries.push(newEntry)
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} else if (rootIsInDom && rootContainsTarget) {
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// If the new entry intersection ratio has crossed any of the
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// thresholds, add a new entry.
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if (this._hasCrossedThreshold(oldEntry, newEntry)) {
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this._queuedEntries.push(newEntry)
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}
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} else {
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// If the root is not in the DOM or target is not contained within
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// root but the previous entry for this target had an intersection,
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// add a new record indicating removal.
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if (oldEntry && oldEntry.isIntersecting) {
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this._queuedEntries.push(newEntry)
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}
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}
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}, this)
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if (this._queuedEntries.length) {
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this._callback(this.takeRecords(), this)
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}
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}
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/**
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* Accepts a target and root rect computes the intersection between then
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* following the algorithm in the spec.
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* TODO(philipwalton): at this time clip-path is not considered.
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* https://w3c.github.io/IntersectionObserver/#calculate-intersection-rect-algo
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* @param {Element} target The target DOM element
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* @param {Object} rootRect The bounding rect of the root after being
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* expanded by the rootMargin value.
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* @return {?Object} The final intersection rect object or undefined if no
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* intersection is found.
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* @private
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*/
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IntersectionObserver.prototype._computeTargetAndRootIntersection = function(
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target,
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rootRect
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) {
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// If the element isn't displayed, an intersection can't happen.
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if (window.getComputedStyle(target).display == 'none') return
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var targetRect = getBoundingClientRect(target)
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var intersectionRect = targetRect
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var parent = getParentNode(target)
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var atRoot = false
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while (!atRoot) {
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var parentRect = null
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var parentComputedStyle =
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parent.nodeType == 1 ? window.getComputedStyle(parent) : {}
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// If the parent isn't displayed, an intersection can't happen.
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if (parentComputedStyle.display == 'none') return
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if (parent == this.root || parent == document) {
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atRoot = true
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parentRect = rootRect
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} else {
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// If the element has a non-visible overflow, and it's not the <body>
|
||
|
|
// or <html> element, update the intersection rect.
|
||
|
|
// Note: <body> and <html> cannot be clipped to a rect that's not also
|
||
|
|
// the document rect, so no need to compute a new intersection.
|
||
|
|
if (
|
||
|
|
parent != document.body &&
|
||
|
|
parent != document.documentElement &&
|
||
|
|
parentComputedStyle.overflow != 'visible'
|
||
|
|
) {
|
||
|
|
parentRect = getBoundingClientRect(parent)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If either of the above conditionals set a new parentRect,
|
||
|
|
// calculate new intersection data.
|
||
|
|
if (parentRect) {
|
||
|
|
intersectionRect = computeRectIntersection(parentRect, intersectionRect)
|
||
|
|
|
||
|
|
if (!intersectionRect) break
|
||
|
|
}
|
||
|
|
parent = getParentNode(parent)
|
||
|
|
}
|
||
|
|
return intersectionRect
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the root rect after being expanded by the rootMargin value.
|
||
|
|
* @return {Object} The expanded root rect.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._getRootRect = function() {
|
||
|
|
var rootRect
|
||
|
|
if (this.root) {
|
||
|
|
rootRect = getBoundingClientRect(this.root)
|
||
|
|
} else {
|
||
|
|
// Use <html>/<body> instead of window since scroll bars affect size.
|
||
|
|
var html = document.documentElement
|
||
|
|
var body = document.body
|
||
|
|
rootRect = {
|
||
|
|
top: 0,
|
||
|
|
left: 0,
|
||
|
|
right: html.clientWidth || body.clientWidth,
|
||
|
|
width: html.clientWidth || body.clientWidth,
|
||
|
|
bottom: html.clientHeight || body.clientHeight,
|
||
|
|
height: html.clientHeight || body.clientHeight
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return this._expandRectByRootMargin(rootRect)
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Accepts a rect and expands it by the rootMargin value.
|
||
|
|
* @param {Object} rect The rect object to expand.
|
||
|
|
* @return {Object} The expanded rect.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._expandRectByRootMargin = function(rect) {
|
||
|
|
var margins = this._rootMarginValues.map(function(margin, i) {
|
||
|
|
return margin.unit == 'px'
|
||
|
|
? margin.value
|
||
|
|
: margin.value * (i % 2 ? rect.width : rect.height) / 100
|
||
|
|
})
|
||
|
|
var newRect = {
|
||
|
|
top: rect.top - margins[0],
|
||
|
|
right: rect.right + margins[1],
|
||
|
|
bottom: rect.bottom + margins[2],
|
||
|
|
left: rect.left - margins[3]
|
||
|
|
}
|
||
|
|
newRect.width = newRect.right - newRect.left
|
||
|
|
newRect.height = newRect.bottom - newRect.top
|
||
|
|
|
||
|
|
return newRect
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Accepts an old and new entry and returns true if at least one of the
|
||
|
|
* threshold values has been crossed.
|
||
|
|
* @param {?IntersectionObserverEntry} oldEntry The previous entry for a
|
||
|
|
* particular target element or null if no previous entry exists.
|
||
|
|
* @param {IntersectionObserverEntry} newEntry The current entry for a
|
||
|
|
* particular target element.
|
||
|
|
* @return {boolean} Returns true if a any threshold has been crossed.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._hasCrossedThreshold = function(
|
||
|
|
oldEntry,
|
||
|
|
newEntry
|
||
|
|
) {
|
||
|
|
// To make comparing easier, an entry that has a ratio of 0
|
||
|
|
// but does not actually intersect is given a value of -1
|
||
|
|
var oldRatio =
|
||
|
|
oldEntry && oldEntry.isIntersecting ? oldEntry.intersectionRatio || 0 : -1
|
||
|
|
var newRatio = newEntry.isIntersecting
|
||
|
|
? newEntry.intersectionRatio || 0
|
||
|
|
: -1
|
||
|
|
|
||
|
|
// Ignore unchanged ratios
|
||
|
|
if (oldRatio === newRatio) return
|
||
|
|
|
||
|
|
for (var i = 0; i < this.thresholds.length; i++) {
|
||
|
|
var threshold = this.thresholds[i]
|
||
|
|
|
||
|
|
// Return true if an entry matches a threshold or if the new ratio
|
||
|
|
// and the old ratio are on the opposite sides of a threshold.
|
||
|
|
if (
|
||
|
|
threshold == oldRatio ||
|
||
|
|
threshold == newRatio ||
|
||
|
|
threshold < oldRatio !== threshold < newRatio
|
||
|
|
) {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns whether or not the root element is an element and is in the DOM.
|
||
|
|
* @return {boolean} True if the root element is an element and is in the DOM.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._rootIsInDom = function() {
|
||
|
|
return !this.root || containsDeep(document, this.root)
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns whether or not the target element is a child of root.
|
||
|
|
* @param {Element} target The target element to check.
|
||
|
|
* @return {boolean} True if the target element is a child of root.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._rootContainsTarget = function(target) {
|
||
|
|
return containsDeep(this.root || document, target)
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Adds the instance to the global IntersectionObserver registry if it isn't
|
||
|
|
* already present.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._registerInstance = function() {
|
||
|
|
if (registry.indexOf(this) < 0) {
|
||
|
|
registry.push(this)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Removes the instance from the global IntersectionObserver registry.
|
||
|
|
* @private
|
||
|
|
*/
|
||
|
|
IntersectionObserver.prototype._unregisterInstance = function() {
|
||
|
|
var index = registry.indexOf(this)
|
||
|
|
if (index != -1) registry.splice(index, 1)
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the result of the performance.now() method or null in browsers
|
||
|
|
* that don't support the API.
|
||
|
|
* @return {number} The elapsed time since the page was requested.
|
||
|
|
*/
|
||
|
|
function now() {
|
||
|
|
return window.performance && performance.now && performance.now()
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Throttles a function and delays its executiong, so it's only called at most
|
||
|
|
* once within a given time period.
|
||
|
|
* @param {Function} fn The function to throttle.
|
||
|
|
* @param {number} timeout The amount of time that must pass before the
|
||
|
|
* function can be called again.
|
||
|
|
* @return {Function} The throttled function.
|
||
|
|
*/
|
||
|
|
function throttle(fn, timeout) {
|
||
|
|
var timer = null
|
||
|
|
return function() {
|
||
|
|
if (!timer) {
|
||
|
|
timer = setTimeout(function() {
|
||
|
|
fn()
|
||
|
|
timer = null
|
||
|
|
}, timeout)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Adds an event handler to a DOM node ensuring cross-browser compatibility.
|
||
|
|
* @param {Node} node The DOM node to add the event handler to.
|
||
|
|
* @param {string} event The event name.
|
||
|
|
* @param {Function} fn The event handler to add.
|
||
|
|
* @param {boolean} opt_useCapture Optionally adds the even to the capture
|
||
|
|
* phase. Note: this only works in modern browsers.
|
||
|
|
*/
|
||
|
|
function addEvent(node, event, fn, opt_useCapture) {
|
||
|
|
if (typeof node.addEventListener == 'function') {
|
||
|
|
node.addEventListener(event, fn, opt_useCapture || false)
|
||
|
|
} else if (typeof node.attachEvent == 'function') {
|
||
|
|
node.attachEvent('on' + event, fn)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Removes a previously added event handler from a DOM node.
|
||
|
|
* @param {Node} node The DOM node to remove the event handler from.
|
||
|
|
* @param {string} event The event name.
|
||
|
|
* @param {Function} fn The event handler to remove.
|
||
|
|
* @param {boolean} opt_useCapture If the event handler was added with this
|
||
|
|
* flag set to true, it should be set to true here in order to remove it.
|
||
|
|
*/
|
||
|
|
function removeEvent(node, event, fn, opt_useCapture) {
|
||
|
|
if (typeof node.removeEventListener == 'function') {
|
||
|
|
node.removeEventListener(event, fn, opt_useCapture || false)
|
||
|
|
} else if (typeof node.detatchEvent == 'function') {
|
||
|
|
node.detatchEvent('on' + event, fn)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the intersection between two rect objects.
|
||
|
|
* @param {Object} rect1 The first rect.
|
||
|
|
* @param {Object} rect2 The second rect.
|
||
|
|
* @return {?Object} The intersection rect or undefined if no intersection
|
||
|
|
* is found.
|
||
|
|
*/
|
||
|
|
function computeRectIntersection(rect1, rect2) {
|
||
|
|
var top = Math.max(rect1.top, rect2.top)
|
||
|
|
var bottom = Math.min(rect1.bottom, rect2.bottom)
|
||
|
|
var left = Math.max(rect1.left, rect2.left)
|
||
|
|
var right = Math.min(rect1.right, rect2.right)
|
||
|
|
var width = right - left
|
||
|
|
var height = bottom - top
|
||
|
|
|
||
|
|
return (
|
||
|
|
width >= 0 &&
|
||
|
|
height >= 0 && {
|
||
|
|
top: top,
|
||
|
|
bottom: bottom,
|
||
|
|
left: left,
|
||
|
|
right: right,
|
||
|
|
width: width,
|
||
|
|
height: height
|
||
|
|
}
|
||
|
|
)
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Shims the native getBoundingClientRect for compatibility with older IE.
|
||
|
|
* @param {Element} el The element whose bounding rect to get.
|
||
|
|
* @return {Object} The (possibly shimmed) rect of the element.
|
||
|
|
*/
|
||
|
|
function getBoundingClientRect(el) {
|
||
|
|
var rect
|
||
|
|
|
||
|
|
try {
|
||
|
|
rect = el.getBoundingClientRect()
|
||
|
|
} catch (err) {
|
||
|
|
// Ignore Windows 7 IE11 "Unspecified error"
|
||
|
|
// https://github.com/w3c/IntersectionObserver/pull/205
|
||
|
|
}
|
||
|
|
|
||
|
|
if (!rect) return getEmptyRect()
|
||
|
|
|
||
|
|
// Older IE
|
||
|
|
if (!(rect.width && rect.height)) {
|
||
|
|
rect = {
|
||
|
|
top: rect.top,
|
||
|
|
right: rect.right,
|
||
|
|
bottom: rect.bottom,
|
||
|
|
left: rect.left,
|
||
|
|
width: rect.right - rect.left,
|
||
|
|
height: rect.bottom - rect.top
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return rect
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns an empty rect object. An empty rect is returned when an element
|
||
|
|
* is not in the DOM.
|
||
|
|
* @return {Object} The empty rect.
|
||
|
|
*/
|
||
|
|
function getEmptyRect() {
|
||
|
|
return {
|
||
|
|
top: 0,
|
||
|
|
bottom: 0,
|
||
|
|
left: 0,
|
||
|
|
right: 0,
|
||
|
|
width: 0,
|
||
|
|
height: 0
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Checks to see if a parent element contains a child elemnt (including inside
|
||
|
|
* shadow DOM).
|
||
|
|
* @param {Node} parent The parent element.
|
||
|
|
* @param {Node} child The child element.
|
||
|
|
* @return {boolean} True if the parent node contains the child node.
|
||
|
|
*/
|
||
|
|
function containsDeep(parent, child) {
|
||
|
|
var node = child
|
||
|
|
while (node) {
|
||
|
|
if (node == parent) return true
|
||
|
|
|
||
|
|
node = getParentNode(node)
|
||
|
|
}
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Gets the parent node of an element or its host element if the parent node
|
||
|
|
* is a shadow root.
|
||
|
|
* @param {Node} node The node whose parent to get.
|
||
|
|
* @return {Node|null} The parent node or null if no parent exists.
|
||
|
|
*/
|
||
|
|
function getParentNode(node) {
|
||
|
|
var parent = node.parentNode
|
||
|
|
|
||
|
|
if (parent && parent.nodeType == 11 && parent.host) {
|
||
|
|
// If the parent is a shadow root, return the host element.
|
||
|
|
return parent.host
|
||
|
|
}
|
||
|
|
return parent
|
||
|
|
}
|
||
|
|
|
||
|
|
// Exposes the constructors globally.
|
||
|
|
window.IntersectionObserver = IntersectionObserver
|
||
|
|
window.IntersectionObserverEntry = IntersectionObserverEntry
|
||
|
|
})(window, document)
|