Support Importing Fragments

[brettjurgens]

brought up by @zamiang here: #127 (comment)

essentially, in a query that looks like:

#import "./path/to/fragment"

query DoSomething {
  ...FragmentFromImport
}

should import the fragment & generate the appropriate typings

[zamiang]

While I'm thinking about it. It seems like there are (at least) 3 approaches that we could take here.

1. when generating a type for a query, gql2ts would load any imported fragment and inline the fragment in the generated type for the query
2. a new function that generates a single namespace file for a single fragment (would create a global type for each fragment) ie: FragmentFromImport.d.ts
3. generate a larger file (much like schema.d.ts) of types for all fragments and then have the generated types for queries import and use those fragments. (struggling a bit with imagining this approach)

Do you feel strongly about any particular way of doing this?

[brettjurgens]

So I was leaning towards option 1, option 2 seems more difficult with minimal gain.

I've only given it a little thought, but the caveats I've come up with, so far, are:

• @gql2ts/from-schema doesn't know where the file is located, which will complicate relative imports

  • allow passing either the file's directory to resolve the imports (this seems like it might be the best option)
    • cli/possible webpack loader would be able to do this automatically
    • API users can pass the additional option
  • allow passing an array of fragment definitions

• nested imports (i.e. a fragment imports another fragment and so on...)

regardless of these, I think option 1 should be relatively trivial

[brettjurgens]

adding this to #163