Graphql-code-generator: TS and Nullable types, again

[iamdanthedev]

Hi!

I know it was discussed and closed here https://github.com/dotansimha/graphql-code-generator/issues/138
However I think the current implementation is not totally correct

By default, every type is nullable - it's legitimate to return null as any of the scalar types.
from http://graphql.org/graphql-js/basic-types/

Now when generating interfaces it marks the field optional but the value remains non-nullable.
Optional field is good for convinience (as discussed in issue 138), but non-nullable value leaves us to return either value or undefined. And we can't return null, which is against the spec.

// schema.gql
extend type Query {
   nutrient(_id: String): Nutrient
}

// types.generated.ts
export interface Query {
  nutrient?: Nutrient; 
}

// resolver.ts
const Query: TypedResolver<Types.Query> = {

  nutrient: async (root, ctx) => {
    const result = await db.nutrients.findOne({ _id: new ObjectID(ctx._id) }); **// Promise(Nutruent | null)**
    return result || undefined; **// ugly trick**
  }

};

IMHO, the solution would be to generate types like this:

// types.generated.ts
export interface Query {
  nutrient?: Nutrient | null; 
}

Thanks!

[dotansimha]

It makes sense. Fixing it now!

[dotansimha]

@rasdaniil @altschuler fixed in 0.8.14 :)

[iamdanthedev]

Thanks @dotansimha !