const HeaderWordCasingExceptions: Record = { ct: 'CT', etag: 'ETag', te: 'TE', www: 'WWW', x: 'X', xss: 'XSS', } export function canonicalHeaderName(name: string): string { return name .toLowerCase() .split('-') .map((word) => HeaderWordCasingExceptions[word] || word.charAt(0).toUpperCase() + word.slice(1)) .join('-') }