Error when unsubscribing from BLE.startScanWithOptions()

[tkem]

When unsubscribing from an Observable returned by BLE.startScanWithOptions(), which should implicitly call BLE.stopScan(), I get the following error on Android:

Error: Error: Uncaught (in promise): TypeError: callback.success.apply is not a function
TypeError: callback.success.apply is not a function
    at Object.callbackFromNative (cordova.js:293)

Doing some debugging in Chrome, it looks like cordova.callbacks[callbackId] contains

"{"success":[],"fail":{"reportDuplicates":true}}"

which happen to be the arguments as passed to startScanWithOptions(), and not the success/failure callbacks for BLE.stopScan(), as apparently expected.

Having a look at the BLE plugin source (https://github.com/driftyco/ionic-native/blob/master/src/plugins/ble.ts#L218) , the following seems suspicious:

 @Cordova({
    observable: true,
    clearFunction: 'stopScan',
    clearWithArgs: true
  })
static startScanWithOptions(services: string[], options: {reportDuplicates?: boolean} | any): Observable<any> { return; }

AFAIK, clearWithArgs: true would pass the arguments of the decorated function to the clearFunction, too. However, BLE.stopScan() does not expect any arguments (except for success/failure callbacks), so this is likely the cause for this.

Note that the same (clearWithArgs: true) also applies to BLE.startScan(), but I'm not using this and so I cannot verify that the same error occurs.