Connect external HID device (Keyboard or remote camera trigger)

Yeah - your other comment about bonding from the neighbor thread did the trick.

This is working now:

var gatt;

function onInit() {

  NRF.requestDevice({
    filters: [{namePrefix: "AB"}]
  }).then((device)=> {
    console.log("FOUND", device.id, device.name);
    return device.gatt.connect();
  }).then((device)=>{
    gatt = device;
    console.log("CONNECTED", device);
    return gatt.startBonding();
  }).then(function() {
    console.log("BONDED", gatt.getSecurityStatus());
    return gatt.getPrimaryService(0x1812);
  }).then((service)=>{
    console.log("SERVICE", service);
    return service.getCharacteristic(0x2a4d);
  }).then((char)=>{
    console.log("CHAR", char);
    char.on("characteristicvaluechanged",(e)=>{
      console.log("EVENT", e.target.value);
    });
    return char.startNotifications();
  }).then(()=>{
    console.log("DONE");
    return true;
  }).catch((err)=>{
    console.log("ERROR", err);
  });
}

onInit();

For a button press I get:

EVENT DataView: {
  "buffer": new Uint8Array([2, 0]).buffer,
  "byteOffset": 0, "byteLength": 2 }

and for a release:

EVENT DataView: {
  "buffer": new ArrayBuffer(2),
  "byteOffset": 0, "byteLength": 2 }

The only thing is that when I pull the power from Espruino the bonding seems to be lost and the blue LED on the remote begins flashing again.

This does not happen when bonded to Laptop/Phone. Maybe it's about the whitelisting.

But I could live with that.
Thanks @Gordon for the hint!