一起执行功能

Question

我怀疑如何同时执行两个功能。我想我应该使用Promise.All（），但是我不知道如何使用。

您好，代码结构如下：

scan1(){
this.manager.startDeviceScan(null, null, (error, device) => {
      if (error) {
        return;
      }
      if (
        (device.name == this.model_dx(this.props.Model)) ||
        (device.name == this.model_sx(this.props.Model))
      ) {
        this.setState({ deviceId1: device.id });
        this.manager.stopDeviceScan();
        this.setState({deviceName1: device})
        console.log("(this.state.deviceName1 = device:): " + this.state.deviceName1);
        device
          .connect()
          .then(() => {
            console.log(" ");
            this.scan2();
       //..code...

scan2(){
this.manager.startDeviceScan(null, null, (error, device) => {
      if (error) {
        return;
      }
      if (
        (device.name == this.model_sx(this.props.Model)) ||
        (device.name == this.model_dx(this.props.Model))
      ) {
        this.manager.stopDeviceScan();
        this.setState({ deviceId2: device.id });
        this.setState({deviceName2: device})
        device
          .connect()
          .then(() => {
            this.deviceService1(this.state.deviceName1);
            this.deviceService2(this.state.deviceName2);
       // .... code.... 

deviceService1(device) {
    console.log("device.name: " + device.name)
    if (device.name == this.model_dx(this.props.Model) ||
      device.name == this.model_sx(this.props.Model)) { 
      device
        .discoverAllServicesAndCharacteristics()
        .then(() => {
          console.log("(this.setupNotifications1")
          this.setupNotifications1(device);
        })
        //... code..

  deviceService2(device) {
    console.log("device.name: " + device.name)
    if (device.name == this.model_sx(this.props.Model) ||
      device.name == this.model_dx(this.props.Model)) { 
      device
        .discoverAllServicesAndCharacteristics()
        .then(() => {
          console.log("(this.setupNotifications2")
          this.setupNotifications2(device);
        })
       //... code...

在两个功能setupNotifications1（设备）和setupNotifications2（设备）中，我从外部设备恢复数据。这里的问题实际上是这样的：我先从一台设备恢复数据，然后再从另一台设备恢复数据，因此我从第一台设备中获取了更多数据。

现在我该如何一起执行这两个功能setupNotification？

谢谢！