NestJS GraphQL报错：无法确定expectedInvestmentSupportInfo的输出类型

我创建了名为UploadedInvestmentDocumentInput的DTO，并关联到expectedInvestmentSupportInfo属性，但报错：

uncaughtException: Cannot determine a GraphQL output type for the "expectedInvestmentSupportInfo"

注释opportunity-account.output.ts中的expectedInvestmentSupportInfo字段后错误消失，请问该字段缺少什么装饰器或属性？

opportunity-account.input.ts #

import { UploadedDocumentInput } from '@app/dto/common.input';
import {
  Field,
  InputType, OmitType, PickType, registerEnumType,
} from '@nestjs/graphql';
import { Type } from 'class-transformer';
import { IsEnum, ValidateNested } from 'class-validator';

import {
  ExpectedInvestmentSupportInfoType,
  SourceOfFundsType,
} from '@/generated-cbms-api-client';

import { OpportunityAccount } from './opportunity-account.response';

registerEnumType(SourceOfFundsType, { name: 'SourceOfFundsType' });
registerEnumType(ExpectedInvestmentSupportInfoType, { name: 'ExpectedInvestmentSupportInfoType' });

@InputType()
export class UploadedInvestmentDocumentInput extends OmitType(UploadedDocumentInput, ['documentType'], InputType) {
  @IsEnum(ExpectedInvestmentSupportInfoType)
  @Field(() => ExpectedInvestmentSupportInfoType)
  documentType: ExpectedInvestmentSupportInfoType;
}

@InputType()
export class UpsertAnticipatedInvestmentActivitiesInput extends PickType(
  OpportunityAccount,
  [
    'isPlanningInvestIn12Months',
    'anticipatedInvestmentOpportunitiesCountRange',
    'investmentDescription',
  ],
  InputType,
) {
  @ValidateNested({ each: true })
  @Type(() => UploadedInvestmentDocumentInput)
  @Field(() => [UploadedInvestmentDocumentInput], { description: 'Expected investment support info' })
  expectedInvestmentSupportInfo: UploadedInvestmentDocumentInput[];
}

UploadedDocumentInput（公共DTO） #

import { Field, InputType } from '@nestjs/graphql';
import { FileUpload, GraphQLUpload } from 'graphql-upload';

@InputType()
export class UploadedDocumentInput {
  @Field(() => Number)
  documentType: number;

  @Field(() => GraphQLUpload)
  frontSideDoc: FileUpload;

  @Field(() => GraphQLUpload, { nullable: true })
  backSideDoc?: FileUpload;
}

opportunity-account.output.ts #

class UploadedInvestmentDocumentResponse extends OmitType(UploadedDocumentResponse, ['documentType'], InputType) {
  @IsEnum(ExpectedInvestmentSupportInfoType)
  @Field(() => ExpectedInvestmentSupportInfoType)
  documentType: ExpectedInvestmentSupportInfoType;
}

@ObjectType()
export class OpportunityAccount extends AccountsCommonDetails {
  @IsMongoId()
  @Field(() => String, { description: 'Customer id' })
  customerId: string;

// 我认为问题出在这里（注释此字段后错误消失！）

  @IsEnum(UploadedInvestmentDocumentResponse)
  @ValidateNested({ each: true })
  @Type(() => UploadedInvestmentDocumentResponse)
  @Field(() => [UploadedInvestmentDocumentResponse], { description: 'Expected investment support info' })
  expectedInvestmentSupportInfo: UploadedInvestmentDocumentResponse[];
}

核心问题 #

1. UploadedInvestmentDocumentResponse未标记为GraphQL输出类型
   该类是用于GraphQL响应的DTO，但既没有添加@ObjectType()装饰器，还错误地在OmitType中传入了InputType作为类型参数——GraphQL无法识别未标记输出类型的类作为字段类型。

2. 错误使用@IsEnum验证器
   expectedInvestmentSupportInfo是对象数组，而非枚举值，你给它添加的@IsEnum(UploadedInvestmentDocumentResponse)完全无效，@IsEnum仅能用于枚举类型的字段验证。

修复后的opportunity-account.output.ts代码 #

import { ObjectType, OmitType, Field } from '@nestjs/graphql';
import { ValidateNested } from 'class-validator';
import { Type } from 'class-transformer';
import { ExpectedInvestmentSupportInfoType } from '@/generated-cbms-api-client';
import { UploadedDocumentResponse } from './path-to-uploaded-document-response'; // 确保导入正确的父类

// 标记为GraphQL输出类型，同时修正OmitType的类型参数
@ObjectType()
export class UploadedInvestmentDocumentResponse extends OmitType(UploadedDocumentResponse, ['documentType'], ObjectType) {
  @Field(() => ExpectedInvestmentSupportInfoType)
  documentType: ExpectedInvestmentSupportInfoType;
}

@ObjectType()
export class OpportunityAccount extends AccountsCommonDetails {
  @Field(() => String, { description: 'Customer id' })
  customerId: string;

  // 移除错误的@IsEnum，保留正确的嵌套验证和类型转换
  @ValidateNested({ each: true })
  @Type(() => UploadedInvestmentDocumentResponse)
  @Field(() => [UploadedInvestmentDocumentResponse], { description: 'Expected investment support info' })
  expectedInvestmentSupportInfo: UploadedInvestmentDocumentResponse[];
}

关键修复点总结 #

• 所有用于GraphQL响应的类必须添加@ObjectType()装饰器，使用OmitType/PickType生成输出类型时，第三个参数要传ObjectType。
• 仅在枚举类型字段上使用@IsEnum验证器，对象/数组类型字段不要误用。

内容的提问来源于stack exchange，提问作者Abdullah Ch