charcode-is-valid-xml-name-character/types/index.d.ts

Does a given character belong to XML spec's "Production 4 OR 4a" type (is acceptable for XML element's name)

declare function isProduction4(char: string): boolean;
declare function isProduction4a(char: string): boolean;

export {
  isProduction4,
  isProduction4a,
  isProduction4 as validFirstChar,
  isProduction4a as validSecondCharOnwards,
};