Modules - what am I doing wrong

Thanks For have a look Robin is this a better layout ?

var devices;
var gatt;
var DevName="e0:7d:ea:0c:03:29";
var serviceUUID="00001623-1212-efde-1623-785feabcd123";
var characteristicUUID="00001624-1212-efde-1623-785feabcd123";
var MessageToSend=[0x81, 0x00, 0x11, 0x51, 0x00, 0x64];
pinMode(D15, 'input_pulldown');
global.LED2=D2;

NRF.connect("e0:7d:ea:0c:03:29").then(function(g) {
  console.log("Starting connecting");
  gatt = g;
  return gatt.getPrimaryService("00001623-1212-efde-1623-785feabcd123");
}).then(function(service) {
  return service.getCharacteristic("00001624-1212-efde-1623-785feabcd123");
}).then(function(characteristic) {
  return characteristic.writeValue(MessageToSend);
}).then(function() {
  //gatt.disconnect();
  console.log("Done!");
});

function send_message() {
  console.log("Moving Train");
  NRF.nfcSend(new Uint8Array([0x81, 0x00, 0x11, 0x51, 0x00, 0x64]));
}

function train_disconnect() {
  console.log("Disconnecting");
  gatt.disconnect();
}

setInterval(function() {
  digitalWrite(LED2, digitalRead(D15));
  if (digitalRead(D15) == 1) {
    send_message();
  }
  console.log("Button pressed", digitalRead(D15));
}, 300);