toJSON should not throw an error

[qharlie]

Is your feature request related to a problem? Please describe. Having toJSON throw an error breaks serialization to local storage and Im guessing other serialization

Describe the solution you'd like Have toJSON call dfd.toJSONode directly

Describe alternatives you've considered I'm integrating with a third party library which calls toJSON , there is no other work around.

Additional context Add any other context or screenshots about the feature request here.