Help Required To Automatically Reconnect to BLE Browser

Hi (help !),
I am struggling to make the BangleJS automatically reconnect to my BLE browser (on my iPhone or on my Raspberry-Pi).
Initial connection is good but when I move the watch out of BLE range and then move it back again I would like it to reconnect automatically.

I have tried adding the following to my copy of UART.js:-

device.addEventListener('gattserverdisco­nnected', function disconnected() {
            setTimeout(reconnect,180000);
            function reconnect()
            {device.gatt.connect();}});

The event fires and the browser displays a bluetooth icon as though it is connected but I seem to have lost the UART object because data transfers will not work afterwards.
If anyone has any ideas I would be very grateful !
Thanks very much :-)
Mark