code: function isValidRadix(radix) {
      return !(
          (radix.type === "Literal" && typeof radix.value !== "number") ||
          (radix.type === "Identifier" && radix.name === "undefined")
      );
  }
docs: Checks whether a given node is a valid value of radix or not.
  
  The following values are invalid.
  
  - A literal except numbers.
  - undefined.
  
  @param {ASTNode} radix - A node of radix to check.
  @returns {boolean} `true` if the node is valid.