OAuth2 authentication callback failing due to missing property

[nyaaao]

I'm getting and error TypeError: Cannot set property 'accessToken' of undefined in https://github.com/feathersjs/feathers-authentication/blob/master/src/services/oauth2/index.js#L44 probably due to _json property is missing. Looking at other Strategies' implementation I see this in passport-facebook (set here: https://github.com/jaredhanson/passport-facebook/blob/master/lib/strategy.js#L179), but not, for example, in passport-google. My Strategy provider does not set it as well.

Can this be made conditional?