Crash after BluetoothRemoteGATTServer.disconnect() (async TypeError in PeripheralHandles.deleteHandles)

[kayahr]

Description

After calling disconnect() on a connected BluetoothRemoteGATTServer, the process crashes asynchronously on the next event-loop turn. disconnect() itself does not throw. The error is not catchable from userland because it happens inside the adapter cleanup code and results in an unhandled rejection / process abort.

Reproduction

import { bluetooth } from "webbluetooth";

const SERVICE_UUID = "…"; // any service your peripheral advertises

function nextTick(): Promise<void> {
    return new Promise((r) => setTimeout(r, 0));
}

const device = await bluetooth.requestDevice({
    filters: [{ services: [SERVICE_UUID] }],
    optionalServices: [SERVICE_UUID],
});
console.log("Device:", device.name);

const server = await device.gatt.connect();
console.log("Connected");

server.disconnect();
console.log("Disconnected");

await nextTick(); // crash happens here
console.log("Exit"); // Never reached

Expected behavior

server.disconnect() should disconnect cleanly without throwing later, and the program should continue normally.

Actual behavior

Crash on next event loop turn:

$ node test.js
Device: BleServer
Connected
Disconnected
/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:78
    var s = typeof Symbol === "function" && Symbol.iterator, m = s && o[s], i = 0;
                                                                       ^

TypeError: undefined is not iterable (cannot read property Symbol(Symbol.iterator))
    at __values (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:78:72)
    at PeripheralHandles.deleteHandles (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:194:35)
    at SimplebleAdapter.<anonymous> (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:468:30)
    at step (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:72:23)
    at Object.next (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:53:53)
    at /tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:47:71
    at new Promise (<anonymous>)
    at __awaiter (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:43:12)
    at SimplebleAdapter.disconnect (/tmp/ble-client/node_modules/webbluetooth/dist/adapters/simpleble-adapter.js:457:16)
    at BluetoothRemoteGATTServerImpl.disconnect (/tmp/ble-client/node_modules/webbluetooth/dist/server.js:131:28)

Environment

• Node.js 24.13.0
• webbluetooth 3.4.0
• Debian Linux 13

Additional notes

Looks like PeripheralHandles.deleteHandles() iterates over a collection that can be undefined during disconnect cleanup. A guard for missing handle maps (or initializing them consistently) might fix it.