[gatsby-transformer-json] add graphql-type-json to allow better handling of JSON files

Summary

I’m currently trying to add my package.json file to GraphQL. I already created a plugin which sources single files instead of directories with helpers from gatsby-source-filesystem. But this plugin does not allow me to get all from the key dependencies since GraphQL is explicit. After searching, I found a type plugin for graphql which adds this cap.

https://github.com/taion/graphql-type-json

It would be great if this plugin could be added to gatsby-transformer-json or if we could extend the documentation so that someone can add it by himself.

Here is an Apollo tutorial: https://www.apollographql.com/docs/apollo-server/schema/scalars-enums/#using-a-package

I tried to add it with createResolvers but still get some errors (I know it tells we what exactly is wrong but I don’t know what exactly it means). I’m just starting with GraphQL in deep and don’t really know how to add custom scalars. Would appreciate any help and would create a PR if I get a working version for my portfolio as soon as I get free time for it.

ERROR #11321  PLUGIN

"gatsby-node.js" threw an error while running the createResolvers lifecycle:

Cannot find ObjectTypeComposer with name JSON

Basic example

If the proposal involves a new or changed API, include a basic code example. Omit this section if it’s not applicable.

Motivation

This would enable easier transformation of JSON files and handling like when using require syntax.

[stefanprobst]

@muuvmuuv

• the content of your package.json file should be available out of the box with:

{
  sitePlugin(name: {eq: "default-site-plugin"}) {
    packageJson {
      dependencies {
        name
        version
      }
    }
  }
}

• Gatsby (via graphql-compose) already includes a JSON scalar. Did that not work for you?

[sidharthachatterjee]

Thanks @stefanprobst ❤️

@muuvmuuv Looks like this is resolved for the moment. Closing this issue for now. Thanks!