react-native with mobx throw error

Question

I implement react native with mobx and i get this errorr

[mobx] Encountered an uncaught exception that was thrown by a reaction or observer component, in: 'Reaction[Reaction@1] Error: [serializr] Failed to find default schema for undefined

root component

    import React, { Component } from 'react';
import {
    View,
    AsyncStorage,
    Text,
} from 'react-native';
import { StackNavigator } from 'react-navigation';

import { observer, Provider } from 'mobx-react/native'
import { create } from 'mobx-persist'
import { AppStore,UserStore } from '../stores'
const stores = { UserStore, AppStore };

import {
    Walkthrough
} from '../screens'

const hydrate = create({
    storage: AsyncStorage
})

let Main = null;

hydrate('appStore', AppStore).then((a) => {
    console.log(a);
    AppStore.done();   
    }
)

hydrate('userStore',UserStore).then((a)=>{
    console.log(a)
    Main = StackNavigator(
        {
            Walkthrough: { screen: Walkthrough },

        }, {
            headerMode: 'none',
            lazy: true,
            initialRouteName: 'Walkthrough',
        }
    )
})



@observer
class Root extends Component {
    constructor(props){
        super(props);
        this.state = {

        }
    }


    render(){
        // const ready =  UserStore.storeHydrated &&  AppStore.storeHydrated;
        const ready = false;
        return (
            <View>
            {!ready &&  
                <View><Text>Splash screen component</Text></View>}

            </View>

        )  
    }
}

export default Root;

AppStore

    import { observable, action, computed } from 'mobx'
import { persist } from 'mobx-persist'

class AppStore {
    @observable storeHydrated = false
    @observable requesting = false

    constructor(){
        console.log("AppStore")
    }

    @action setRequesting(){
        this.requesting = !this.requesting;
    }

    @action done(){
        //this.storeHydrated = true
    }


}


const appStore = new AppStore();
export default appStore;

UserStore

    import { observable, action, computed } from 'mobx'
import { persist } from 'mobx-persist'

class UserStore {
    @persist @observable first_name;
    @persist @observable last_name;
    @persist @observable email;
    @persist @observable tasks;
    @persist @observable storeHydrated = false;
    @persist @observable alreadyRegister = false;

    constructor(){
        this.setUser = this.setUser.bind(this);
        console.log("userStore")
    }

    @action setUser(data){
        this.first_name = data.first_name
        this.last_name = data.last_name;
        this.email = data.email;
        this.tasks = data.tasks;
    }

    @action done(){
        //this.storeHydrated = true;
        // if(this.alreadyRegister){
        //     this.getUserDetails();
        // }
    }

    @action setIsFirstTimeInApp(firstTIme){
        this.firstTimeInApp = firstTIme;
    }


}


const user = new UserStore();
export default user;

what I already tried to do is to delete the app and run again and still nothing changed and it throw me the same error.

Answer 1

the problem is

@persist @observable storeHydrated = false;

inside the UserStore should not be persist since it's a value the restarts on every load of the app.

since it's in persist the value of true is saved in storage after the first run.

so use:

@observable storeHydrated = false;

then the StackNavigator, Main, is rendered before you have defined it.

extra tip:

when using @persist @observable varName , you should always initialize a value, even null, since the serialization of 'undefined' is not supported properly so it should look like this: @persist @observable varName = null (or any thing that fits like empty string , 0 , true , false etc.) and for special schemes it should be:

@persist('list') @observable varName = [] 
@persist('object') @observable varName = null
@persist('map') @observable varName = new Map()