Function: forEachHeaderValue()

forEachHeaderValue(input, headerName, consumer): void

Invokes consumer once per value for headerName, case-insensitive.

• Record input: if the field is an array (e.g. repeated Set-Cookie), consumer runs once per array item.
• Headers input: uses get(name) (which spec-joins repeats with , ) except for Set-Cookie, which uses getSetCookie() so each cookie is delivered separately.

Parameters

input

HeaderLike | null | undefined

headerName

string

consumer

(value) => void

Returns

void

Example

forEachHeaderValue(req, "x-trace-id", (v) => spans.push(v));     // Express
forEachHeaderValue(c.req.raw, "set-cookie", (v) => log(v));      // Hono
forEachHeaderValue(headersInstance, "cookie", parse);            // fetch