code: function join(joiner, ...values) {
      if (values.length > 0) {
        return concat([],...values).join(joiner);
      }
  
      // Manually currying
      return (...values) => join(joiner, ...values);
    }
docs: Converts array elements to string joined by specified joiner.
  @param joiner Joins array elements
  @param values different individual arrays