ServerResponse#appendHeader not implemented

[cyco130]

The appendHeader method of ServerResponse from the node:http module doesn't seem to have been implemented. This makes it impossible to return multiple Set-Cookie headers from the server when using node:http (I tried a few other ways like passing an array to setHeader or calling writeHead with an array value for set-cookie but none seemed to work).

System Info

Deno version: 1.35.3
OS: macOS 13.4.1
CPU: (10) arm64 Apple M1 Max

[cyco130]

Temporary workaround (forces Headers#set to accept an array, probably not standards-compliant):

const oldSet = Headers.prototype.set;
Headers.prototype.set = function set(
  this: Headers,
  key: string,
  value: string | string[]
) {
  if (Array.isArray(value)) {
    this.delete(key);
    value.forEach((v) => this.append(key, v));
  } else {
    oldSet.call(this, key, value);
  }
};

[bartlomieju]

@cyco130 do you have some reproduction code? We have this method implemented here:

deno/ext/node/polyfills/_http_outgoing.ts

Line 257 in 02865cb

appendHeader(name, value) {

[cyco130]

The problem is that ServerResponse doesn't extend OutgoingMessage as it does on Node (it extends Writable instead).

Reproduction is simply:

import { ServerResponse } from "node:http";
console.assert(typeof new ServerResponse({}).appendHeader === "function");

[bartlomieju]

Ah, good catch! Thanks for pointing this out.