Support additional fields

[mizdra]

blocked by: #73

Problem

Alias is a feature that allows you to change the result of a field to any name you want.

• https://graphql.org/learn/queries/

This can be used to generate a response with a field that does not exist in Author type.

const query = graphql`
  query ExampleQuery @raw_response_type {
    author(id: "1") {
      id
      name
      name2 # alias
    }
  }
`;
const data = useClientQuery(query);
console.log(data);
// output:
// {
//   author: {
//     id: "1",
//     name: "Mikami Komata",
//     name2: "Mikami Komata",
//   },
// }

However, graphql-codegen-typescript-fabbrica cannot generate alias-derived fields. This makes it difficult to build responses for queries that use aliases.

const AuthorFactory = defineAuthorFactory({
  defaultFields: {
    id: dynamic(({ seq }) => `Author-${seq}`),
    name: "Komata Mikami",
  },
});

const author = await AuthorFactory.build();
//    ^? { id: string, name: string }

const dummyResponse: ExampleQuery$rawResponse = { author };
//    ^^^^^^^^^^^^^ error: author.name2 is missing

Solution

Allow defaultFields to accept alias-derived fields. The interface is designed with reference to Quramy/prisma-fabbrica#252.

import { type OptionalAuthor } from '../__generated__/fabbrica';
const AuthorFactory = defineAuthorFactory.withAdditionalFields<{ name2: OptionalAuthor['name'] }>()({
  defaultFields: {
    id: dynamic(({ seq }) => `Author-${seq}`),
    name: "Komata Mikami",
    name2: "Komata Mikami", // alias-derived field
  },
});

const author = await AuthorFactory.build();
//    ^? { id: string, name: string, name2: string }

const dummyResponse: ExampleQuery$rawResponse = { author }; // ok

Drawbacks

In the current implementation of graphql-codegen-typescript-fabbrica, fields not included in type are treated as transient fields. transient fields are not included in the built data.

• https://github.com/mizdra/graphql-codegen-typescript-fabbrica/tree/9ac221aaefe886097b2fcc732fc1493f467e49f9#transient-fields

Therefore, to implement this proposal, we have to change the interface of transient fields.

[mizdra]

graphql-codegen-typescript-fabbrica excludes properties other than field (__typename, id, name) of its type from the build result.

• https://stackblitz.com/edit/playground-graphql-codegen-typescript-fabbrica-nvazzz?file=__generated__%2Ffabbrica.ts%3AL17,src%2Findex.test.ts&view=editor
• https://stackblitz.com/edit/playground-graphql-codegen-typescript-fabbrica-nvazzz?file=__generated__%2Ffabbrica.ts%3AL38,src%2Findex.test.ts,node_modules%2F%40mizdra%2Fgraphql-codegen-typescript-fabbrica%2Fdist%2Fhelper%2Ffactory.d.ts,node_modules%2F%40mizdra%2Fgraphql-codegen-typescript-fabbrica%2Fdist%2Fhelper%2Findex.d.ts&view=editor

• graphql-codegen-typescript-fabbrica/src/helper/factory.ts

  Line 67 in 7b14060

  typeFieldNames,

• graphql-codegen-typescript-fabbrica/src/helper/field-resolver.ts

  Line 103 in 077a10b

  return Object.fromEntries(Object.entries(fields).filter(([key]) => fieldNames.includes(key))) as any;

So, if you pass a field such as name2 to the build function, it will not be included in the build result. This limitation is implemented for transient fields.

Therefore, implementing alias-derived fields requires a change in the implementation of transient fields.

[mizdra]

This feature supports any additional fields, not just fields for aliases.

I think the feature should be renamed from "alias fields" to "additional fields".