code: function toDefault(val, def) {
      if (is_1.isValue(val) && !(is_1.isEmpty(val) && !is_1.isEmpty(def)))
          return val;
      return is_1.isValue(def) ? def : null;
  }
docs: To Default
  Returns a default value when provided if
  primary value is null or undefined. If neither
  then null is returned.
  
  @param val the value to return if defined.
  @param def an optional default value to be returned.