Unable to read from BL651 with react-native-ble-plx

[WQvist]

I'm using React Native and the BLE package react-native-ble-plx on my Ubuntu machine.

According to the docs, I've done the following:
1. Scanned for devices
2. Connected to device
3. device.discoverAllServicesAndCharacteristics
4. writeCharacteristicWithResponseForDevice

My problem lies in reading the response I get from sending my command.

RX characteristic is writable, but TX is only notifiable and not readable. Therefore I need to monitor the characteristic with monitorCharacteristicForDevice, however I can't get this to function.

I never recieve neither 'monitor success',  'Error at receiving data from device' nor 'Monitor failure' in the code below.

How do I read the return?

monitorDevice = () => {
    this.setState({monitoring: true})
    console.log(this.state.servicesDiscovered)
    if(this.state.servicesDiscovered){
        {this.manager.monitorCharacteristicForDevice(this.state.connectedTo,
            SERVICE_UUID,
            TX_CHARACTERISTIC,
            (error, characteristic) => {
                if (error) {
                    console.error("Error at receiving data from device", error);
                    return     
                }
                else {
                    this.setState({monitoring: true})
                    console.log('monitor success')
                    console.log('monitor success' + characteristic.value);
                    this.state.messagesRecieved.push(characteristic.value)
                }
            })
        }
      }
      else{
          console.log("Monitor failure")
    }
}
 
checkBattery = () => {
    if(this.state.monitoring){
        this.manager.writeCharacteristicWithResponseForDevice(this.state.connectedTo,
            SERVICE_UUID,
            RX_CHARACTERISTIC,
            "YmF0dGVyeQ==")
        .then(characteristic => {
            console.log("Successfully sent: " + characteristic.value)
            return
        })
        .catch(err => {
            console.log(err)
        })
    }
    else{
        alert("Not monitoring")
    }
}

[Kenneth]

Do not have any experience with this, maybe better directed to React Native community?

[WQvist]

Instead of sending an encoded string, such as "c3RyaW5n", I needed to use base64.encode("string")