Unable to build after wrapping root reducer with optimistic

[drewandre]

Following the readme instructions, I receive the error "Unhandled JS Exception: Unexpected token u in JSON at position 0" after wrapping my root reducer with optimistic like so:

import { optimistic } from 'redux-optimistic-ui'
...
const rootReducer = optimistic(combineReducers({
  session,
  notices,
  feed,
  user,
  jobSites,
  upload,
  post
}))

My JS bundle works fine but react-native (running version 0.57) will not launch because of this. Is there a step I'm missing, or am I misunderstanding how to "feed it my reducer"?