@polymer/polymer/polymer-legacy.js

The Polymer library makes it easy to create your own web components. Give your element some markup and properties, and then use it on a site. Polymer provides features like dynamic templates and data binding to reduce the amount of boilerplate you need to

/**
@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
*/

import { LegacyElementMixin } from './lib/legacy/legacy-element-mixin.js';
export { Polymer } from  './lib/legacy/polymer-fn.js';
/* template elements */
import './lib/legacy/templatizer-behavior.js';
import './lib/elements/dom-bind.js';
import './lib/elements/dom-repeat.js';
import './lib/elements/dom-if.js';
import './lib/elements/array-selector.js';
/* custom-style */
import './lib/elements/custom-style.js';
/* bc behaviors */
import './lib/legacy/mutable-data-behavior.js';
/* import html-tag to export html */
export { html } from './lib/utils/html-tag.js';

// bc
export const Base = LegacyElementMixin(HTMLElement).prototype;