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-rw-r--r--static/lazyload.js180
1 files changed, 180 insertions, 0 deletions
diff --git a/static/lazyload.js b/static/lazyload.js
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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;
+});