Typesafety when a plugin adds a field to context

[ahmedosama7450]

Hi there!

I am making a nexus plugin, which computes expensive operations (e.g. database fetch) and passes them into context to be used by different sub-resolvers

An example usage of the plugin can be something like:

queryField("postQuery", {
    ...
    
    // This is the field that my plugin adds which return an object of the values to be computed
    compute: (_, { id }, { db })=> {
      return {
        post: fetchPost(db);
      }
    },
    
    authorize: (_, __, {db, computed}, )=> {
      // use computed.post           (not type-safe)
    },
    
    validate: (_,__,{computed})=> {
       // use computed.post      (not type-safe)
    },
    
    resolver: (_,__,)=> {
      // use computed.post      (not type-safe)
    }
  
}
)

Everything is working fine except that It's not type-safe.

Here is how the context is typed right now

export interface Context  {
  ...
  computed?: Record<string, any>;
}

---

Proposed Solution

The plugin factory method should accept a parameter called additonalContextType which is a string e.g.

type SomeType<T> =  {
 computed: T
}

plugin(
  {
    additionlContextType: "SomeType<T>"
  }
)

Then all additionalContextType parameters from all plugins should be merged with the original context type

So, Right now one problem is solved, the plugin is able to add an additional type to context, but still this T generic should be the return type of the compute function. How can that be achieved ?