/**
* @license
* Copyright (c) 2017 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';
// global for (1) existence means `WebComponentsReady` will file,
// (2) WebComponents.ready == true means event has fired.
window.WebComponents = window.WebComponents || {};
var name = 'webcomponents-loader.js';
// Feature detect which polyfill needs to be imported.
var polyfills = [];
if (!('import' in document.createElement('link'))) {
polyfills.push('hi');
}
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');
}
// NOTE: any browser that does not have template or ES6 features
// must load the full suite (called `lite` for legacy reasons) of polyfills.
if (!('content' in document.createElement('template')) || !window.Promise || !Array.from ||
// Edge has broken fragment cloning which means you cannot clone template.content
!(document.createDocumentFragment().cloneNode() instanceof DocumentFragment)) {
polyfills = ['lite'];
}
if (polyfills.length) {
var script = document.querySelector('script[src*="' + name +'"]');
var newScript = document.createElement('script');
// Load it from the right place.
var replacement = 'webcomponents-' + polyfills.join('-') + '.js';
var url = script.src.replace(name, replacement);
newScript.src = url;
// NOTE: this is required to ensure the polyfills are loaded before
// *native* html imports load on older Chrome versions. This *is* CSP
// compliant since CSP rules must have allowed this script to run.
// In all other cases, this can be async.
if (document.readyState === 'loading' && ('import' in document.createElement('link'))) {
document.write(newScript.outerHTML);
} else {
document.head.appendChild(newScript);
}
} else {
// Ensure `WebComponentsReady` is fired also when there are no polyfills loaded.
// however, we have to wait for the document to be in 'interactive' state,
// otherwise a rAF may fire before scripts in <body>
var fire = function() {
requestAnimationFrame(function() {
window.WebComponents.ready = true;
document.dispatchEvent(new CustomEvent('WebComponentsReady', {bubbles: true}));
});
};
if (document.readyState !== 'loading') {
fire();
} else {
document.addEventListener('readystatechange', function wait() {
fire();
document.removeEventListener('readystatechange', wait);
});
}
}
})();