Undefined Unstated Container in a React Native Component using React Navigation - react-native

Question

My problem is That I want to access a Container in a component but it seems to be undefined.
undefined alert image
I am using Unstated and as you can see this is my code in the container file (login-container.js):
import { Container } from 'unstated'
class LoginContainer extends Container {
constructor(props){
super(props)
this.state = {
stepNumber: 0,
}
}
}
export default new LoginContainer()
And this is app.js:
import React, { Component } from 'react'
import { createStackNavigator, createSwitchNavigator } from 'react-navigation'
import { Provider } from 'unstated'
import LoginContainer from './containers/login-container'
import Home from './screens/home'
import Splash from './screens/splash'
import Login from './screens/login'
import Intro from './screens/intro'
export default class App extends Component {
render() {
return (
<Provider inject={[LoginContainer]}>
<AuthStack/>
</Provider>
)
}
}
const SplashStack = createStackNavigator(...)
const AppStack = createStackNavigator(...)
const AuthStack = createStackNavigator(
{
Intro: { screen: Intro},
Login: { screen: Login}
},
{
headerMode: "none",
initialRouteName: "Intro"
}
)
const SwitchNavigator = createSwitchNavigator(...)
And this would be login.js:
import React, { Component } from 'react'
import { Text, View } from 'react-native'
export default class Login extends Component {
constructor(props){
super(props)
}
render() {
// const { state: {stepNumber} } = this.props.loginContainer
alert(this.props.LoginContainer)
return (
<View>
<Text> someText </Text>
</View>
)
}
}
I previously tried to use Subscribe component to inject the container to my app but I got the same thing I am getting here.
Using
- react-native 0.58.6
- react-navigation 2.13.0 (due to some bugs in v3)
- unstated 2.1.1

Answer 1

What's really great about Unstated is how simple it is to implement.
Just wrap your render component in Unstated's <Subscribe to></Subscribe> tags and you're good to go. Whenever you setState() in the Container, all Components that Subscribe to it get re-rendered with the Container's updated state property values available to them.
import React, { Component } from 'react';
import { Text, View } from 'react-native';
import { Subscribe } from 'unstated';
import LoginContainer from './containers/login-container';
export default class Login extends Component {
constructor(props){
super(props)
}
render() {
return (
<Subscribe to={[LoginContainer, AnotherContainer]}>
{(container, another) => (
<View>
<Text>{container.state.stepNumber}</Text>
</View>
})
</Subscribe>
);
}
}
UPDATE: Or do it in this HOC way. After creating this:
WithUnstated.js
import React, { PureComponent } from "react";
import { Subscribe } from "unstated";
import DefaultStore from "../store/DefaultStore";
const withUnstated = (
WrappedComponent,
Stores = [DefaultStore],
navigationOptions
) =>
class extends PureComponent {
static navigationOptions = navigationOptions;
render() {
return (
<Subscribe to={Stores}>
{(...stores) => {
const allStores = stores.reduce(
(acc, v) => ({ ...acc, [v.displayName]: { ...v } }),
{}
);
return <WrappedComponent {...allStores} {...this.props} />;
}}
</Subscribe>
);
}
};
export default withUnstated;
Then wrap your component like so:
import React, { Component } from 'react';
import { Text, View } from 'react-native';
import { Subscribe } from 'unstated';
import LoginContainer from './containers/login-container';
import AnotherContainer from './containers/another-container';
class Login extends Component {
constructor(props){
super(props)
}
render() {
const {LoginContainer: container} = this.props;
return (
<View>
<Text>{container.state.stepNumber}</Text>
</View>
);
}
}
export default withUnstated(Login, [LoginContainer, AnotherContainer])