使用 OpenHarmony  4.0 release 最新发布的 release note 中的镜像，使用 rk3568 运行  Sample 仓 中 ArkTSDistributedCalc 项目。

在项目打包前，已修改 SDK 中 配置项目为系统App，应用为 API 10 应用，IDE 使用 OpenHarmony  4.0 release 最新发布的 release note 中的版本。

在 RemoteDeviceModel.ets 文件中，如下代码
 

export class RemoteDeviceModel {
  public deviceList: Array<distributedDeviceManager.DeviceBasicInfo> | undefined = undefined
  public discoverList: Array<distributedDeviceManager.DeviceBasicInfo> = []
  private callback: () => void = () => {
  }
  private authCallback: () => void = () => {
  }
  private deviceManager: distributedDeviceManager.DeviceManager | null = null

  registerDeviceListCallback(callback: Callback<void>) {
    Logger.info(TAG, `deviceManager type =${typeof (this.deviceManager)} ,${JSON.stringify(this.deviceManager)} ,${JSON.stringify(this.deviceManager) === '{}'}`)
    if (typeof (this.deviceManager) !== 'undefined') {
      this.registerDeviceListCallbackImplement(callback)
      return
    }
    Logger.info(TAG, 'deviceManager.createDeviceManager begin')
    try {
      let dmInstance = distributedDeviceManager.createDeviceManager('ohos.samples.etsdistributedcalc');
      this.deviceManager = dmInstance
      this.registerDeviceListCallbackImplement(callback)
      Logger.info(TAG, `createDeviceManager callback returned, value= ${JSON.stringify(this.deviceManager)}`)
    } catch (error) {
      Logger.error(TAG, `createDeviceManager throw code:${error.code} message:${error.message}`)
    }
    Logger.info(TAG, 'deviceManager.createDeviceManager end')
  }

this.deviceManager 类型判断为 object，日志如附件。导致程序异常。

 为什么定义为 null 的变量在 typeof 时会 输出 为object？