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这里的问题是当我使用 plainToClass() 时，我的构造函数将抛出未定义构造函数参数的错误。

这是我的 Mongo de 查询，它返回 DeviceOperationsModel[] 数组。需要使用该库的辅助函数使用类转换器进行类型检查。

public async find(query: object): Promise<DeviceOperationsModel[]> {
        this.appLoggerService.info(`Finding records on the basis of the following query: ${JSON.stringify(query)}`,
            DeviceOperationsDbService.name);
        return await this.deviceOperationsModel.find(query).lean().exec();
    }

这是 DeviceOperationsModel 模型类。有嵌套的类对象


import { DeviceOperationsRequestModel } from './device-operations-request.model';
import { DeviceOperationsResponseModel } from './device-operations-response.model';

export class DeviceOperationsModel {
    readonly correlationId: string;
    readonly deviceId: string;
    readonly requestType: string;
    readonly request: DeviceOperationsRequestModel;
    readonly response: DeviceOperationsResponseModel;
    readonly createdAt: Date;
    readonly systemName: string;
    status: number;
    statusDescription: string;

    constructor(deviceOperationsData: any, correlationId: string, systemName: string, deviceOperationsResponseData?: any) {
        this.correlationId = correlationId;
        this.systemName = systemName;
        this.deviceId = deviceOperationsData.deviceId;
        this.requestType = deviceOperationsData.requestType;
        this.request = deviceOperationsData;
        this.response = deviceOperationsResponseData;
        this.createdAt = deviceOperationsData.createdAt;
        this.status = deviceOperationsData.status;
        this.statusDescription = deviceOperationsData.statusDescription;
    }
}

这是 deviceOperationsData 类定义。

import { DeviceOperationsDestinationBlobModel } from './device-operations-destination-blob.model';

export class DeviceOperationsRequestModel {
    readonly serviceTimeoutInSeconds: number;
    readonly agentTimeoutInSeconds: number;
    readonly errorOnDisconnection: boolean;
    readonly destinationBlob: DeviceOperationsDestinationBlobModel;
    readonly metadata: object;
    readonly agentRetryCount: number;
    readonly agentRetryIntervalInSeconds: number;
    readonly progressUpdate: boolean;

    constructor(deviceOperation: any) {
        this.serviceTimeoutInSeconds = deviceOperation.serviceTimeoutInSeconds;
        this.agentTimeoutInSeconds = deviceOperation.agentTimeoutInSeconds;
        this.errorOnDisconnection = deviceOperation.errorOnDisconnection;
        this.destinationBlob = deviceOperation.destinationBlob;
        this.metadata = deviceOperation.metadata;
        this.agentRetryCount = deviceOperation.agentRetryCount;
        this.agentRetryIntervalInSeconds = deviceOperation.agentRetryIntervalInSeconds;
        this.progressUpdate = deviceOperation.progressUpdate;
    }
}

等等。

在这里对 Mongo DB 数据进行类型转换的最佳方法是什么？

我试过了，但是

try { 
const result = await this.deviceOperationsModel.find(query).lean().exec(); 
return plainToClass(DeviceOperationsModel, result as object[]); 
} catch (error) { 
console.log(error); 
}

但是得到了相关性，设计，系统名称等是未定义的。

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1 回答 1

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在类转换器文档中给出的示例中，类定义没有构造函数。见这里。

所以，我建议在没有构造函数的情况下这样做。

但是，您似乎期望DeviceOperationsModel构造函数中的数据不仅仅是对象。plainToClass()只接受一个对象和一个类定义。

如果您有可能不会出现在对象中的可选属性，请在类定义中将它们标记为可选。

此外，您不需要await在find函数中。它返回一个 Promise，并且您没有对函数中的 Promise 结果做任何事情。您甚至不需要标记它async（但也许您之前正在检查它以进行调试......）。

于 2020-07-24T05:43:29.817 回答