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/*! |
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* Lazy Load - JavaScript plugin for lazy loading images |
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* |
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* Copyright (c) 2007-2019 Mika Tuupola |
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* |
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* Licensed under the MIT license: |
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* http://www.opensource.org/licenses/mit-license.php |
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* |
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* Project home: |
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* https://appelsiini.net/projects/lazyload |
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* |
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* Version: 2.0.0-rc.2 |
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* |
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*/ |
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|
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(function (root, factory) { |
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if (typeof exports === "object") { |
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module.exports = factory(root); |
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} else if (typeof define === "function" && define.amd) { |
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define([], factory); |
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} else { |
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root.LazyLoad = factory(root); |
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} |
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}) (typeof global !== "undefined" ? global : this.window || this.global, function (root) { |
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|
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"use strict"; |
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|
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if (typeof define === "function" && define.amd){ |
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root = window; |
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} |
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|
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const defaults = { |
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src: "data-src", |
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srcset: "data-srcset", |
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selector: ".lazyload", |
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root: null, |
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rootMargin: "0px", |
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threshold: 0 |
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}; |
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|
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/** |
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* Merge two or more objects. Returns a new object. |
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* @private |
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* @param {Boolean} deep If true, do a deep (or recursive) merge [optional] |
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* @param {Object} objects The objects to merge together |
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* @returns {Object} Merged values of defaults and options |
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*/ |
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const extend = function () { |
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|
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let extended = {}; |
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let deep = false; |
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let i = 0; |
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let length = arguments.length; |
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|
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/* Check if a deep merge */ |
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if (Object.prototype.toString.call(arguments[0]) === "[object Boolean]") { |
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deep = arguments[0]; |
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i++; |
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} |
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|
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/* Merge the object into the extended object */ |
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let merge = function (obj) { |
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for (let prop in obj) { |
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if (Object.prototype.hasOwnProperty.call(obj, prop)) { |
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/* If deep merge and property is an object, merge properties */ |
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if (deep && Object.prototype.toString.call(obj[prop]) === "[object Object]") { |
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extended[prop] = extend(true, extended[prop], obj[prop]); |
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} else { |
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extended[prop] = obj[prop]; |
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} |
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} |
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} |
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}; |
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|
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/* Loop through each object and conduct a merge */ |
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for (; i < length; i++) { |
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let obj = arguments[i]; |
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merge(obj); |
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} |
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|
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return extended; |
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}; |
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|
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function LazyLoad(images, options) { |
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this.settings = extend(defaults, options || {}); |
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this.images = images || document.querySelectorAll(this.settings.selector); |
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this.observer = null; |
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this.init(); |
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} |
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|
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LazyLoad.prototype = { |
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init: function() { |
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|
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/* Without observers load everything and bail out early. */ |
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if (!root.IntersectionObserver) { |
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this.loadImages(); |
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return; |
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} |
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|
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let self = this; |
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let observerConfig = { |
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root: this.settings.root, |
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rootMargin: this.settings.rootMargin, |
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threshold: [this.settings.threshold] |
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}; |
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|
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this.observer = new IntersectionObserver(function(entries) { |
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Array.prototype.forEach.call(entries, function (entry) { |
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if (entry.isIntersecting) { |
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self.observer.unobserve(entry.target); |
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let src = entry.target.getAttribute(self.settings.src); |
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let srcset = entry.target.getAttribute(self.settings.srcset); |
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if ("img" === entry.target.tagName.toLowerCase()) { |
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if (src) { |
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entry.target.src = src; |
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} |
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if (srcset) { |
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entry.target.srcset = srcset; |
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} |
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} else { |
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entry.target.style.backgroundImage = "url(" + src + ")"; |
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} |
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} |
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}); |
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}, observerConfig); |
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|
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Array.prototype.forEach.call(this.images, function (image) { |
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self.observer.observe(image); |
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}); |
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}, |
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|
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loadAndDestroy: function () { |
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if (!this.settings) { return; } |
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this.loadImages(); |
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this.destroy(); |
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}, |
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|
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loadImages: function () { |
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if (!this.settings) { return; } |
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|
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let self = this; |
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Array.prototype.forEach.call(this.images, function (image) { |
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let src = image.getAttribute(self.settings.src); |
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let srcset = image.getAttribute(self.settings.srcset); |
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if ("img" === image.tagName.toLowerCase()) { |
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if (src) { |
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image.src = src; |
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} |
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if (srcset) { |
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image.srcset = srcset; |
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} |
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} else { |
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image.style.backgroundImage = "url('" + src + "')"; |
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} |
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}); |
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}, |
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|
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destroy: function () { |
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if (!this.settings) { return; } |
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this.observer.disconnect(); |
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this.settings = null; |
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} |
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}; |
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|
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root.lazyload = function(images, options) { |
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return new LazyLoad(images, options); |
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}; |
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|
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if (root.jQuery) { |
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const $ = root.jQuery; |
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$.fn.lazyload = function (options) { |
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options = options || {}; |
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options.attribute = options.attribute || "data-src"; |
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new LazyLoad($.makeArray(this), options); |
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return this; |
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}; |
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} |
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|
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return LazyLoad; |
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}); |
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|
