How to manual disconnect from BLE UART server

Yes, an automatic retry has crossed my mind, but I wanted to understand why these thing "happed" first.

Based on https://www.espruino.com/Puck.js+Controlling+Other+Pucks I made a version with busy/connected flags.

// Are we busy?
var busy = false;

// The device, if we're connected
var connected = false;

var d;

// The 'tx' characteristic, if connected
var txCharacteristic = false;
var rxCharacteristic = false;

function getData(){

// Function to call 'toggle' on the other Puck
  if (!busy) {
    print("Getting data now");
    busy = true;
    if (!connected) {
      NRF.connect("30:ae:a4:5d:b3:f2 public").then(function(device) {
        // print(device);
        d=device;
        return d.getPrimaryService("6e400001-b5a3-f393-e0a9-e50e24dcca9e");
      }).then(function(s) {
        return s.getCharacteristic("6e400003-b5a3-f393-e0a9-e50e24dcca9e");
      }).then(function(c) {
        // print(c);
        rxCharacteristic = c;
        busy = false;

  c.on('characteristicvaluechanged', function(event) {
    buf =E.toString(event.target.value.buffer);
    
    print("RX  " + buf);

    
    if(buf.includes("Quit")){
      print("Quit received, disconnecting now");
      d.disconnect();
      connected=false;
      busy = false;
    }
  });
  
  return c.startNotifications();
        
      });
    }
  }

}

getData();

This works brilliant.

• Every time I upload the sketch connection is made to the UART server without any errors or complaints.
  
• And the disconnect is fired at receiving of "Quit", and recognised by the UART server.
  
  

Output of 2 subsequent uploads, no errors.

 ____                 _
|  __|___ ___ ___ _ _|_|___ ___
|  __|_ -| . |  _| | | |   | . |
|____|___|  _|_| |___|_|_|_|___|
         |_| espruino.com
 2v06 (c) 2019 G.Williams
>Getting data now
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  Quit
Quit received, disconnecting now
>
 ____                 _
|  __|___ ___ ___ _ _|_|___ ___
|  __|_ -| . |  _| | | |   | . |
|____|___|  _|_| |___|_|_|_|___|
         |_| espruino.com
 2v06 (c) 2019 G.Williams
>Getting data now
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  Quit
Quit received, disconnecting now
Disconnected from Web Bluetooth, Bangle.js 0195
>
 

But when I execute the getData function with a setInterval, the "uncaught errors .... promise....." reappear.

 ____                 _
|  __|___ ___ ___ _ _|_|___ ___
|  __|_ -| . |  _| | | |   | . |
|____|___|  _|_| |___|_|_|_|___|
         |_| espruino.com
 2v06 (c) 2019 G.Williams
>
Getting data now
Getting data now
Uncaught Error: Unhandled promise rejection: BLE error 0x12
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  D07-06-2020 12.23
RX  SAAPL,311.01,+11.5%
RX  SASML,299.45,-4.5%
RX  Hottentottententente
RX  Quit
Quit received, disconnecting now
Getting data now
Uncaught Error: Unhandled promise rejection: Disconnected
> 

I assume that in the subsequent uploads the Espruino environment is fully reset, and the errors do not occur, but using setInterval the environment is not "cleaned" in a similar way.