stub-demo.html

<link rel="import" href="../polymer/polymer-element.html">

<dom-module id="stub-demo">
  <script>
    /**
     * `stub-demo`
     * Test examples
     *
     * @customElement
     * @polymer
     * @demo demo/stub-demo.html
     */
    class StubDemo extends Polymer.Element {
        static get is() { return 'stub-demo'; }
        static get properties() {
            return {
                persons: {
                    type: Array,
                    value: [],
                },
                url: {
                    type: String,
                    value: 'http://www.json-generator.com/api/json/get/ceprBrYLCa?indent=2',
                    observer: 'urlChanged',
                },
            };
        }

        static get template() {
            return Polymer.html`
                <style>
                    :host {
                        display: block;
                    }
                </style>

                <template is="dom-if" if="[[persons]]">
                    <ul id="persons">
                        <template is="dom-repeat" items="[[persons]]" as="person">
                            <li>[[person.id]] -> [[person.name]]</li>
                        </template>
                    </ul>
                </template>
            `;
        }

        urlChanged(newUrl, oldUrl) {
            fetch(newUrl).then(response => response.json()).then(persons => this.set('persons', persons));
        }
    }

    window.customElements.define(StubDemo.is, StubDemo);
  </script>
</dom-module>