mobx.js

import Auth0 from '...'

class Auth0Store {
  @observable authenticating = true
  @observable profile = null

  constructor() {
    this.profile = Auth0.currentProfile
    Auth0.on('authenticated', this.authenticatedDone)
  }

  @action() {
    this.authenticating = false
  }
}

export default new Auth0Store()

// In my global store I will have
import Auth0Store from '...'

class Store {
  auth = Auth0Store
}

export default new Store

MST.js

// file auth0_store.js
const Auth0Store = types.model('Auth0Store', {
  authenticating: true,
  profile: types.maybe(types.map({...}))
}).actions(self => {
  return {
    authenticated() {self.authenticating = false}
  }
})

// file store.js

const Store = types.model('Store', {
  auth: Auth0Store
})

// file state.js
import Auth0 from '...'

const state = Store.create({
  auth: Auth0.currentProfile
})

Auth0.on('authenticated', () => {
  state.auth.authenticated()
})