htmlEntities is not defined

function convertHTML(str) {
      // Use Object Lookup to declare as many HTML entities as needed.
// Try to add var before htmlEntities declaration to enable codes passed!
      //Use map function to return a filtered str with all entities changed automatically.
      return str.split('').map(entity => htmlEntities[entity] || entity).join('');

    // test here
    convertHTML("Dolce & Gabbana");

Add var before htmlEntities for codes to pass.

var indeed passes test,. but const is more accurate.