Nestjs Swagger 4 的循环依赖

Question

当我将@nest/swagger库更新到版本 4 时，发生了此错误：

(node:16134) UnhandledPromiseRejectionWarning: Error: A circular dependency has been detected (property key: "customer"). Please, make sure that each side of a bidirectional relationships are using lazy resolvers ("type: () => ClassType").
    at SchemaObjectFactory.createNotBuiltInTypeReference (/opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:182:19)
    at SchemaObjectFactory.mergePropertyWithMetadata (/opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:117:25)
    at /opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:66:35
    at Array.map (<anonymous>)
    at SchemaObjectFactory.exploreModelSchema (/opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:65:52)
    at SchemaObjectFactory.createNotBuiltInTypeReference (/opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:187:37)
    at SchemaObjectFactory.mergePropertyWithMetadata (/opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:117:25)
    at /opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:66:35
    at Array.map (<anonymous>)
    at SchemaObjectFactory.exploreModelSchema (/opt/desenvolvimento/Haizen/projectx_back/node_modules/@nestjs/swagger/dist/services/schema-object-factory.js:65:52)

我的模型类似乎是这样的：

@Entity()
export class Job {
.
.
.
    @ManyToOne(type => Customer, customer => customer.jobs)
    @ApiProperty({ type: Customer })
    customer: Customer;
}

Answer 1

至少在另外三种情况下，您会收到相同的错误消息，即使它们与双向关系无关：

枚举作为类型

错误的：

@ApiProperty({
    type: Salutation
})
public salutation: Salutation;

正确的：

@ApiProperty({
    enum: Salutation
})
public salutation: Salutation;

匿名类型

错误的：

@ApiProperty({
})
public address: {
    street: string;
    houseNumber: string;
};

正确的：

@ApiProperty({
    type: Address
})
public address: Address;

无效的

错误的：

@ApiProperty({
    description: 'This always returns null for downward compatibility'
})
public someLegacyField: null;

正确的：

@ApiProperty({
    description: 'This always returns null for downward compatibility',
    type: String; // needed to avoid error
})
public someLegacyField: null;

我为此在 Github 上创建了一个问题：https ://github.com/nestjs/swagger/issues/1475

Answer 2

对我有用的解决方案是在@ApiProperty() 中声明带有箭头函数的类型，如下所示：

@Entity()
export class Job {
.
.
.
    @ManyToOne(type => Customer, customer => customer.jobs)
    @ApiProperty({ type: () => Customer })
    customer: Customer;
}

Answer 3

对于也遇到此问题的任何人，您可以将type密钥更改enum为@ApiProperty. 这对我有用。