app.js with updated constructor

app.js

import { htmlToElement } from './utils';

export default class App {
  constructor() {
    this.input = document.getElementById('input');
    this.listRoot = document.getElementById('list-root');
    
    // Clone node and its decendants into class property.
    this.emptyState = document.getElementById('empty-state').cloneNode(true);

    this.initInput();
  }
  
  //...
}