Isomorphic hook to access cookies

[wintercounter]

Goals

1. Read cookies values using an isomorphic useCookies hook that works both during CSR and SSR.

Non-Goals

No response

Background

Currently, in Next 14 we have our own isomorphic hook to read cookies. Some layouts are based on cookies. Using this we can avoid hydration mismatches, and we don't need to wait on client side for our app to load to read cookies (which would result in layout shifts).

Here's a simplified example of what we're doing now:

if (typeof window === "undefined") {
  const { cookies } = require(/* webpackIgnore: true */ "next/headers");
  theme = cookies().get("theme")?.value
}

In NextJS 15 cookies() is now async (I know it still works temporarily sync), which doesn't let us migrate.

Proposal

Just like there's isomorphic useSearchParams, useParams, etc., there should be an isomorphic useCookies equivalent.