Export a type for Remix v2 `MetaFunction`s

[onurtemizkan]

Discussed in #9340

^{Originally posted by tmcw October 23, 2023}
I just updated to Remix v2 and the newest version of @sentry/remix. My MetaFunction looks like

export const meta: MetaFunction = ({ data }) => {
 return [
   {
     "sentry-trace": data.sentryTrace || "dev",
   },
   {
     baggage: data.sentryBaggage || "dev",
   }
 ];
};

Previously, this was fine because MetaFunction made data typed any but now that it's typed unknown, TypeScript won't abide by this. The Sentry machinery that inserts sentryTrace seems to be behind the scenes and there's no type helper that I can find that would make this type-check properly.

Also, I see that there are integration tests for this but it doesn't seem like the documentation mentions using MetaFunction anymore?

I don't want to type data as any because it would make any other data access in my meta function unsafe. Is there a good way to solve this problem?

We should export a type to be used in place of MetaFunction for Remix v2.