Array Dictionary

arrayDictionaryProto.js

Array.prototype.toDictionary = function (keySelector, valueSelector = null) {
  const dict = this.reduce((dict, item) => {
    const key = keySelector(item);
    dict[key] = valueSelector ? valueSelector(item) : item;
    return dict;
  }, {});

  // Return an object that is both iterable and accessible by key
  return {
    ...dict,
    [Symbol.iterator]: function* () {
      for (const key in dict) {
        yield dict[key];
      }
    }
  };
};