Polyfill allowing iteration of Safari's HTMLCollection objects

htmlCollectionIteratorPolyfill.js

  // Polyfill because Safari's HTMLCollections are not iterable
  if (typeof HTMLCollection.prototype[Symbol.iterator] !== 'function') {
    HTMLCollection.prototype[Symbol.iterator] = function () {
      let i = 0;
      return {
        next: () => ({done: i >= this.length, value: this.item(i++)})
      }
    };
  }