in packages/core/nano/src/parser.ts [203:213]
function isIdentifierPart(ch: number): boolean {
return (
(ch >= CharacterCodes.A && ch <= CharacterCodes.Z) ||
(ch >= CharacterCodes.a && ch <= CharacterCodes.z) ||
(ch >= CharacterCodes._0 && ch <= CharacterCodes._9) ||
ch === CharacterCodes.$ ||
ch === CharacterCodes._ ||
ch === CharacterCodes.colon ||
ch > CharacterCodes.maxAsciiCharacter
);
}