Extend modules

One of the powerful features of Baeta is the ability to extend existing modules. In this guide, we'll extend our user module by adding photo capabilities.

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

Use the extend keyword to add new fields to existing types from other modules.

2. Generate the types

Generate TypeScript definitions for your new schema:

yarn generate

tip

If you are using the watch mode, types will be automatically generated on each change.

3. Create the resolvers

Create src/modules/user-photos/resolvers.ts to implement the photos field:

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

Create src/modules/user-photos/index.ts to export your extension module:

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

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

Project Structure

Your extended modules should now look like this:

src/modules/
├── user/
│   ├── user.gql
│   ├── resolvers.ts
│   ├── typedef.ts
│   └── index.ts
├── user-photos/
│   ├── user-photos.gql
│   ├── resolvers.ts
│   ├── typedef.ts
│   └── index.ts
└── index.ts # All modules are automatically collected and exported by Baeta

Next Steps

Let's wrap everything up and see how to use our modules.