code: function _setIndex (arrayLike, idx, value, updater) {
      var result = slice(arrayLike, 0, arrayLike.length);
      var n = _toNaturalIndex(idx, result.length);
  
      if (n === n) { // eslint-disable-line no-self-compare
          result[n] = arguments.length === 4 ? updater(arrayLike[n]) : value;
      }
  
      return result;
  }
docs: Sets an index in an array-like object.<br/>
  If provided with an updater function it will use it to update the current value,
  otherwise sets the index to the specified value.
  @private
  @param {ArrayLike} arrayLike
  @param {Number} idx
  @param {*} [value]
  @param {Function} [updater]
  @returns {Array}