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