The request/response headers object.

Key-value pairs of header names and values. Header names are lower-cased.

// Prints something like:
//
// { 'user-agent': 'curl/7.22.0',
//   host: '127.0.0.1:8000',
//   accept: '*' }
console.log(request.headers);

Duplicates in raw headers are handled in the following ways, depending on the header name:

• Duplicates of age, authorization, content-length, content-type, etag, expires, from, host, if-modified-since, if-unmodified-since, last-modified, location, max-forwards, proxy-authorization, referer, retry-after, server, or user-agent are discarded. To allow duplicate values of the headers listed above to be joined, use the option joinDuplicateHeaders in request and createServer. See RFC 9110 Section 5.3 for more information.
• set-cookie is always an array. Duplicates are added to the array.
• For duplicate cookie headers, the values are joined together with ; .
• For all other headers, the values are joined together with , .