code: function setToPairs(set) {
      var index = -1,
          result = Array(set.size);
  
      set.forEach(function(value) {
        result[++index] = [value, value];
      });
      return result;
    }
docs: Converts `set` to its value-value pairs.
  
  @private
  @param {Object} set The set to convert.
  @returns {Array} Returns the value-value pairs.