TypeGraphQL

Question

总结

目标是使用联合声明 return 类型的突变，以表达多种状态：成功和用户错误

能够根据用例select具体类型：

mutation($data: CreateUserInput!) {
  createUser(data: $data){
    ... on CreateUserSuccess {
      user {
        id
      }
    }
   ... on EmailTakenError {
    emailWasTaken
  }
  ... on UserError {
    code
    message
  }
  }
}

使用 TypeGraphQ 实现：

@ObjectType()
class CreateUserSuccess {
  @Field(() => User)
    user: User
}
@ObjectType()
class EmailTakenError {
  @Field()
    emailWasTaken: boolean
}

const mapMutationValueKeyToObjectType = {
  user: CreateUserSuccess,
  code: UserError,
  emailWasTaken: EmailTakenError
}
const CreateUserPayload = createUnionType({
  name: 'CreateUserPayload',
  types: () => [CreateUserSuccess, EmailTakenError, UserError] as const,
  resolveType: mutationValue => {
    const mapperKeys = Object.keys(mapMutationValueKeyToObjectType)
    const mutationValueKey = mapperKeys.find((key) => key in mutationValue)

    return mapMutationValueKeyToObjectType[mutationValueKey]
  }
})

@InputType()
class CreateUserInput implements Partial<User> {
  @Field()
    name: string

  @Field()
    email: string
}

@Resolver(User)
export class UserResolver {
  @Mutation(() => CreateUserPayload)
  createUser (@Arg('data', {
    description: 'Represents the input data needed to create a new user'
  }) createUserInput: CreateUserInput) {
    const { name, email } = createUserInput

    return createUser({ name, email })
  }
}

数据层

export const createUser = async ({
  name, email
}: { name: string; email: string; }) => {
  const existingUser = await dbClient.user.findUnique({
    where: {
      email
    }
  })

  if (existingUser) {
    return {
      code: ErrorCode.DUPLICATE_ENTRY,
      message: "There's an existing user with the provided email.",
      emailWasTaken: true
    }
  }

  return dbClient.user.create({
    data: {
      name,
      email
    }
  })
}

问题

响应不会根据联合解析所有 selected 字段，即使 returning 与不同类型相关的字段也是如此

 if (existingUser) {
    return {
      code: ErrorCode.DUPLICATE_ENTRY,
      message: "There's an existing user with the provided email.",
      emailWasTaken: true
    }
  }

我怀疑这种情况是，如果 EmailTakenError 类型正在 selected，为什么 emailWasTaken 没有在响应中被 returned？

Answer 1

这是我的解释错误

原因是 return 定义为联合类型的解析器确实应该 return 其中之一，在上述情况下，UserError 和 EmailTakenError不会return接受相同的回复

More info on this GitHub discussion

TypeGraphQL - 无法匹配联合的所有接口

TypeGraphQL - Not able to match all the interfaces of a union

graphql

总结

问题