When you're debugging vague observable errors and you can't figure out where it's coming from.
- Add a breakpoint on the line where it throws the error message
- On the call stack, go up a little until you can find the observable instance
- inspect it (usually it'll be the
- check the
_destinationfield and you may find the operator which is added after the faling operator (if there are any)
- if you inspect the destination operator, you may find callback functions you gave to that operator => your app code!