Headers polyfill is missing properties and incorrectly adds getAll

[kentcdodds]

What version of Remix are you using?

1.19.2

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

• Yes

Steps to Reproduce

const headers = new Headers()
headers.getSetCookie // not defined, should be.

The typings aren't there for it in TypeScript either. I've opened an issue about that: microsoft/TypeScript#55270 (this has been fixed)

Also, there are properties in URLSearchParams that aren't on Headers:

• getAll
• sort
• size
• toString (should just be [object Headers]

Expected Behavior

Headers should follow the standard

Actual Behavior

It is missing a property and adds some properties that aren't in the spec.

[haines]

With TypeScript v5.2.2, this causes type checking to fail

node_modules/@remix-run/web-fetch/dist/src/headers.d.ts:19:22 - error TS2420: Class 'import("/Users/andrew/cerbos/spitfire/ui/node_modules/@remix-run/web-fetch/dist/src/headers").default' incorrectly implements interface 'Headers'.
  Property 'getSetCookie' is missing in type 'import("/Users/andrew/cerbos/spitfire/ui/node_modules/@remix-run/web-fetch/dist/src/headers").default' but required in type 'Headers'.

19 export default class Headers extends URLSearchParams implements globalThis.Headers {
                        ~~~~~~~

  node_modules/typescript/lib/lib.dom.d.ts:13447:5
    13447     getSetCookie(): string[];
              ~~~~~~~~~~~~~~~~~~~~~~~~~
    'getSetCookie' is declared here.

[kentcdodds]

The types have been updated in TypeScript

[kentcdodds]

I'm confused why this was removed from v2. This will technically be a breaking change bug fix so it would be better to make this happen as a part of v2.

[MichaelDeBoey]

@brophdawg11 This also breaks all (v2) TS templates