98 lines
3.5 KiB
JavaScript
98 lines
3.5 KiB
JavaScript
(function () {
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"use strict";
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this.JavascriptLoader = (function () {
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function JavascriptLoader() {}
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/**
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* Set of library functions that provide common interface for javascript loading
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* for all module types. All functionality provided by JavascriptLoader should take
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* place at module scope, i.e. don't run jQuery over entire page.
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*
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* executeModuleScripts:
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* Scan the module ('el') for "script_placeholder"s, then:
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*
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* 1) Fetch each script from server
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* 2) Explicitly attach the script to the <head> of document
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* 3) Explicitly wait for each script to be loaded
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* 4) Return to callback function when all scripts loaded
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*/
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JavascriptLoader.executeModuleScripts = function (el, callback) {
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var callbackCalled, completed, completionHandlerGenerator, loaded, placeholders;
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if (!callback) {
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callback = null; // eslint-disable-line no-param-reassign
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}
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placeholders = el.find(".script_placeholder");
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if (placeholders.length === 0) {
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if (callback !== null) {
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callback();
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}
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return [];
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}
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// TODO: Verify the execution order of multiple placeholders
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completed = (function () {
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var i, ref, results;
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results = [];
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for (i = 1, ref = placeholders.length; ref >= 1 ? i <= ref : i >= ref; ref >= 1 ? ++i : --i) {
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results.push(false);
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}
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return results;
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})();
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callbackCalled = false;
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completionHandlerGenerator = function (index) {
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return function () {
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var allComplete, flag, i, len;
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allComplete = true;
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completed[index] = true;
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for (i = 0, len = completed.length; i < len; i++) {
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flag = completed[i];
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if (!flag) {
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allComplete = false;
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break;
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}
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}
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if (allComplete && !callbackCalled) {
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callbackCalled = true;
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if (callback !== null) {
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return callback();
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}
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}
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return undefined;
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};
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};
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// Keep a map of what sources we're loaded from, and don't do it twice.
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loaded = {};
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return placeholders.each(function (index, placeholder) {
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var s, src, src_escaped;
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// TODO: Check if the script already exists in DOM. If so, (1) copy it
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// into memory; (2) delete the DOM script element; (3) reappend it.
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// This would prevent memory bloat and save a network request.
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src = $(placeholder).attr("data-src");
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if (/^\s*(javascript|data|vbscript):/i.test(src)) {
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console.warn("Blocked unsafe script source:", src);
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completionHandlerGenerator(index)();
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return $(placeholder).remove();
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}
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src_escaped = String(src || "")
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.replace(/</g, "%3C")
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.replace(/>/g, "%3E");
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if (!(src_escaped in loaded)) {
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loaded[src_escaped] = true;
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s = document.createElement("script");
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s.setAttribute("src", src_escaped);
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s.setAttribute("type", "text/javascript");
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s.onload = completionHandlerGenerator(index);
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// Need to use the DOM elements directly or the scripts won't execute properly.
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$("head")[0].appendChild(s);
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} else {
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// just call the completion callback directly, without reloading the file
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completionHandlerGenerator(index)();
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}
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return $(placeholder).remove();
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});
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};
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return JavascriptLoader;
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})();
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}).call(this);
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