Can't set multiple Set-Cookie headers in an action

[martinmckenna]

What version of Remix are you using?

1.6.3

Are all your remix dependencies & dev-dependencies using the same version?

• Yes

Steps to Reproduce

1. Have your client reach out to a remix route that as an action like so:

import type { ActionArgs } from "@remix-run/node";
import { createCookie, json } from "@remix-run/node";

import { AUTH_COOKIE, AUTH_EXP_COOKIE } from "app/cookies"

export const setCookie = (key: string, value: any) => {
  const createdCookie = createCookie(key, {
    path: "/",
    sameSite: "lax",
  });
  return createdCookie.serialize(value);
};

export async function action({ request }: ActionArgs) {
  return json(
    {},
    {
      headers: {
        "Set-Cookie": await setCookie(AUTH_COOKIE, ""),
        // @ts-expect-error
        "Set-Cookie": await setCookie(AUTH_EXP_COOKIE, ""),
      },
    }
  );
}

2. Call endpoint
3. Check response headers in dev tools and see there is only 1 Set-Cookie header:

Expected Behavior

See 2 Set-Cookie headers

Actual Behavior

Only seeing 1 Set-Cookie header

[martinmckenna]

this was already brought up a while back after not working with redirect, but someone mentioned it wasn't working in loaders and now i'm seeing similar behavior in an action, so I figured i'd create a new issue:

#231 (comment)

[martinmckenna]

nvm fix is to create a new Headers() instance and add them that way:

  const authCookieHeaders = new Headers();
  authCookieHeaders.append("Set-Cookie", await setCookie(AUTH_COOKIE, ""));
  authCookieHeaders.append("Set-Cookie", await setCookie(AUTH_EXP_COOKIE, ""));

  return json(
    {},
    {
      headers: authCookieHeaders,
    }
  );

[MattyBalaam]

nvm fix is to create a new Headers() instance and add them that way:

  const authCookieHeaders = new Headers();
  authCookieHeaders.append("Set-Cookie", await setCookie(AUTH_COOKIE, ""));
  authCookieHeaders.append("Set-Cookie", await setCookie(AUTH_EXP_COOKIE, ""));

  return json(
    {},
    {
      headers: authCookieHeaders,
    }
  );

This throws a type error in TypeScript

[martinmckenna]

@MattyBalaam can you post your full code. Also i'm on typescript 5.2.2 if that makes a difference