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Version: Next (2.x)

Extend modules

Modules don't have to own their types end-to-end. A second module can extend a type defined elsewhere — useful when different concerns live in different folders. Here we add a photos field to the existing User type from a separate user-photos module.

1. Define the schema​

Create a new schema file at src/modules/user-photos/user-photos.gql:

type UserPhoto {
  id: ID!
  url: String!
}

extend type User {
  photos: [UserPhoto!]
}
tip

The GraphQL extend keyword is what makes this cross-module: any module can add fields to a type declared elsewhere, and Baeta stitches them together at build time.

2. Generate the types​

yarn build

The watcher (started via yarn start) regenerates types on save, so you only run yarn build manually.

3. Implement the resolvers​

src/modules/user-photos/resolvers.ts:

import { UserPhotosModule } from "./typedef.ts";

const { UserPhoto, User } = UserPhotosModule;

export const userPhotosResolver = UserPhoto.$fields({
  id: UserPhoto.id.key("id"),
  url: UserPhoto.url.key("url"),
});

export const userResolver = User.$fields({
  photos: User.photos.resolve(() => {
    return [
      {
        id: "1",
        url: "https://example.com/photo.jpg",
      },
    ];
  }),
});

4. Export the module​

src/modules/user-photos/index.ts:

import { userPhotosResolver, userResolver } from "./resolvers.ts";
import { UserPhotosModule } from "./typedef.ts";

export default UserPhotosModule.$schema({
  UserPhoto: userPhotosResolver,
  User: userResolver,
});

Project structure​

src/modules/
├── user/
│   ├── user.gql
│   ├── resolvers.ts
│   ├── typedef.ts
│   └── index.ts
├── user-photos/
│   ├── user-photos.gql
│   ├── resolvers.ts
│   ├── typedef.ts
│   └── index.ts
└── index.ts          # generated; collects every module in this folder

Next​

Wire everything into a running server.