Apollo DataSource for TypeORM

This is a TypeORM DataSource for Apollo GraphQL Servers. It was adapted from the CosmosDB DataSource

Usage

Use by creating a new class extending the TypeormDataSource, with the desired entity type. Use separate DataSources for each entity type. Initialise the class by passing the entity. Ensure that you have run createConnection before initialising your data sources since this library will use getConnection to obtain a repository. If you have multiple connections you can pass the connectionName in the data source options.

@Entity()
export class UserEntity {
  @PrimaryGeneratedColumn('increment')
  id: number

  @Column({ nullable: true })
  name: string
}

@Entity()
export class PostEntity {
  @PrimaryGeneratedColumn('increment')
  id: number

  @Column({ nullable: true })
  name: string
}

export class UserDataSource extends TypeormDataStore<UserEntity, ApolloContext> {}
export class PostsDataSource extends TypeormDataStore<PostEntity, ApolloContext> {}

const server = new ApolloServer({
  typeDefs,
  resolvers,
  dataSources: () => ({
    users: new UserDataSource(UserEntity),
    posts: new PostsDataSource(PostEntity, { connectionName: 'otherConnection' })
  })
})

Custom queries

TypeormDataSource has a findByQuery method that accepts a function taking a query builder as its only argument, which you can then build a query with. Can be used in resolvers or to create wrappers.

Example of derived class with custom query methods:

export class UserDataSource extends TypeormDataSource<UserEntity, ApolloContext> {
  async findManyByGroupId (groupId: number) {
    return this.findManyByQuery(qb => qb.where('groupId = :groupId', { groupId: 2 }).limit(2))
  }
}

Write Operations

This DataSource has some built-in mutations that can be used to create, update and delete documents.

await context.dataSources.users.createOne(userDoc)

await context.dataSources.users.updateOne(userDoc)

await context.dataSources.users.updateOnePartial(userId, { name: 'Bob' })

await context.dataSources.users.deleteOne(userId)

Batching

Batching is provided on all id-based queries by DataLoader.

Caching

Caching is available on an opt-in basis by passing a ttl option on queries.