Add Node interface codegen functionality

[lkuoch]

There is a known limitation where if you have types implementing the node interface you have to manually define the typenames again.

As a result, this loses type safety and can be easy to miss.

I'm not too sure what the typescript compiler has access to but potentially there could be a codegen step to generate a schema-types.ts with all the typenames that implement node.

Potentially it may require having a special @gqlNodeInterface comment tag in the application code

[lkuoch]

ok i solved this problem by having a script i run before grats which uses oxc-parser to get all the name of all classes that extend the GQLNode interface

[captbaritone]

First of all, I agree with you. This does feel like something Grats should do more to help with.

I've rolled a number of ideas around over the last few years and hadn't yet found one that left me totally happy. But, your post inspired me to come back and explore the problem again.

This is what I've come up with:

#234

Basically Grats can export functions which can map type names to classes and vice versa. This does not result in a "batteries included" Node solution, but it is an unopinionated primitive which enables people to implement a type-safe Node interface.

Curious what you think of an approach like this.