Function isLcHexDigit

http/unstable_structured_fields.ts:509–513

Check if character is a lowercase hex digit (0-9, a-f)

(c: string)

/** Check if character is a lowercase hex digit (0-9, a-f) */
function isLcHexDigit(c: string): boolean {
  const code = c.charCodeAt(0);
  return (code >= CHAR_CODE_0 && code <= CHAR_CODE_9) ||
    (code >= CHAR_CODE_LOWER_A && code <= 102); // 'f' = 102
}

/** RFC 9110 tchar: token characters */
function isTchar(c: string): boolean {