| /** | |
| * Sets a header with case-insensitive deduplication. | |
| * Removes any existing headers whose name matches (case-insensitive), | |
| * then sets the value under the lowercase key. Does not mutate the input object. | |
| * | |
| * @param headers - Existing headers object | |
| * @param name - Header name to set (stored as lowercase) | |
| * @param value - Header value | |
| * @returns New headers object with the header set | |
| */ | |
| export function setHeader( | |
| headers: Record<string, string>, | |
| name: string, | |
| value: string | |
| ): Record<string, string> { | |
| const result = { ...headers } | |
| const nameLower = name.toLowerCase() | |
| for (const key of Object.keys(result)) { | |
| if (key.toLowerCase() === nameLower) { | |
| delete result[key] | |
| } | |
| } | |
| result[nameLower] = value | |
| return result | |
| } | |
| /** | |
| * Normalizes all header keys to lowercase with case-insensitive deduplication. | |
| * When duplicate keys exist (differing only in case), the last value wins. | |
| * Does not mutate the input object. | |
| * | |
| * @param headers - Headers object to normalize | |
| * @returns New headers object with all keys lowercased | |
| */ | |
| export function normalizeHeaders(headers: Record<string, string>): Record<string, string> { | |
| const result: Record<string, string> = {} | |
| for (const [key, value] of Object.entries(headers)) { | |
| result[key.toLowerCase()] = value | |
| } | |
| return result | |
| } | |