A web browser extension that emulates Content Delivery Networks to improve your online privacy. It intercepts traffic, finds supported resources locally, and injects them into the environment. https://www.localcdn.org/
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/**
* @license
* Copyright (c) 2018 The Polymer Project Authors. All rights reserved.
* This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
* The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
* The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
* Code distributed by Google as part of the polymer project is also
* subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
*/
(function() {
'use strict';
/**
* Basic flow of the loader process
*
* There are 4 flows the loader can take when booting up
*
* - Synchronous script, no polyfills needed
* - wait for `DOMContentLoaded`
* - fire WCR event, as there could not be any callbacks passed to `waitFor`
*
* - Synchronous script, polyfills needed
* - document.write the polyfill bundle
* - wait on the `load` event of the bundle to batch Custom Element upgrades
* - wait for `DOMContentLoaded`
* - run callbacks passed to `waitFor`
* - fire WCR event
*
* - Asynchronous script, no polyfills needed
* - wait for `DOMContentLoaded`
* - run callbacks passed to `waitFor`
* - fire WCR event
*
* - Asynchronous script, polyfills needed
* - Append the polyfill bundle script
* - wait for `load` event of the bundle
* - batch Custom Element Upgrades
* - run callbacks pass to `waitFor`
* - fire WCR event
*/
var polyfillsLoaded = false;
var whenLoadedFns = [];
var allowUpgrades = false;
var flushFn;
function fireEvent() {
window.WebComponents.ready = true;
document.dispatchEvent(new CustomEvent('WebComponentsReady', { bubbles: true }));
}
function batchCustomElements() {
if (window.customElements && customElements.polyfillWrapFlushCallback) {
customElements.polyfillWrapFlushCallback(function (flushCallback) {
flushFn = flushCallback;
if (allowUpgrades) {
flushFn();
}
});
}
}
function asyncReady() {
batchCustomElements();
ready();
}
function ready() {
// bootstrap <template> elements before custom elements
if (window.HTMLTemplateElement && HTMLTemplateElement.bootstrap) {
HTMLTemplateElement.bootstrap(window.document);
}
polyfillsLoaded = true;
runWhenLoadedFns().then(fireEvent);
}
function runWhenLoadedFns() {
allowUpgrades = false;
var fnsMap = whenLoadedFns.map(function(fn) {
return fn instanceof Function ? fn() : fn;
});
whenLoadedFns = [];
return Promise.all(fnsMap).then(function() {
allowUpgrades = true;
flushFn && flushFn();
}).catch(function(err) {
console.error(err);
});
}
window.WebComponents = window.WebComponents || {};
window.WebComponents.ready = window.WebComponents.ready || false;
window.WebComponents.waitFor = window.WebComponents.waitFor || function(waitFn) {
if (!waitFn) {
return;
}
whenLoadedFns.push(waitFn);
if (polyfillsLoaded) {
runWhenLoadedFns();
}
};
window.WebComponents._batchCustomElements = batchCustomElements;
var name = 'webcomponents-loader.js';
// Feature detect which polyfill needs to be imported.
var polyfills = [];
if (!('attachShadow' in Element.prototype && 'getRootNode' in Element.prototype) ||
(window.ShadyDOM && window.ShadyDOM.force)) {
polyfills.push('sd');
}
if (!window.customElements || window.customElements.forcePolyfill) {
polyfills.push('ce');
}
var needsTemplate = (function() {
// no real <template> because no `content` property (IE and older browsers)
var t = document.createElement('template');
if (!('content' in t)) {
return true;
}
// broken doc fragment (older Edge)
if (!(t.content.cloneNode() instanceof DocumentFragment)) {
return true;
}
// broken <template> cloning (Edge up to at least version 17)
var t2 = document.createElement('template');
t2.content.appendChild(document.createElement('div'));
t.content.appendChild(t2);
var clone = t.cloneNode(true);
return (clone.content.childNodes.length === 0 ||
clone.content.firstChild.content.childNodes.length === 0);
})();
// NOTE: any browser that does not have template or ES6 features
// must load the full suite of polyfills.
if (!window.Promise || !Array.from || !window.URL || !window.Symbol || needsTemplate) {
polyfills = ['sd-ce-pf'];
}
if (polyfills.length) {
var url;
var polyfillFile = 'bundles/webcomponents-' + polyfills.join('-') + '.js';
// Load it from the right place.
if (window.WebComponents.root) {
url = window.WebComponents.root + polyfillFile;
} else {
var script = document.querySelector('script[src*="' + name +'"]');
// Load it from the right place.
url = script.src.replace(name, polyfillFile);
}
var newScript = document.createElement('script');
newScript.src = url;
// if readyState is 'loading', this script is synchronous
if (document.readyState === 'loading') {
// make sure custom elements are batched whenever parser gets to the injected script
newScript.setAttribute('onload', 'window.WebComponents._batchCustomElements()');
document.write(newScript.outerHTML);
document.addEventListener('DOMContentLoaded', ready);
} else {
newScript.addEventListener('load', function () {
asyncReady();
});
newScript.addEventListener('error', function () {
throw new Error('Could not load polyfill bundle' + url);
});
document.head.appendChild(newScript);
}
} else {
// if readyState is 'complete', script is loaded imperatively on a spec-compliant browser, so just fire WCR
if (document.readyState === 'complete') {
polyfillsLoaded = true;
fireEvent();
} else {
// this script may come between DCL and load, so listen for both, and cancel load listener if DCL fires
window.addEventListener('load', ready);
window.addEventListener('DOMContentLoaded', function() {
window.removeEventListener('load', ready);
ready();
})
}
}
})();