Resolving promise issue with react native and Async Storage

I have spent days now and have read numerous articles and answers here and I can not wrap my head around this. Below is just my last attempt at this.

I just need to use data stored in Async Storage and use it inside App()

Can someone please take a look at this simple App() starting code and explain in the planest possible way how to resolve the promise here.

import { StatusBar } from 'expo-status-bar'
import React, { useState, useEffect } from 'react'
import { StyleSheet, Text, View } from 'react-native'
import { Button, Input } from 'react-native-elements'
import Icon from 'react-native-vector-icons/FontAwesome'
import AsyncStorage from '@react-native-async-storage/async-storage'

export default async function App () {
  let [userData, setUserData] = useState({})

  useEffect(() => {
    storeData('test2')
    getItem()
  }, [])

  const storeData = async value => {
    try {
      await AsyncStorage.setItem('@storage_Key', value)
    } catch (e) {
      // saving error
    }
  }

  const getItem = async () => {
    const value = await AsyncStorage.getItem('@storage_Key')
    return value
  }

  userData = getItem()
  console.log(userData)

  return (
    <View style={styles.container}>
      <Text>Local storing: {userData}</Text>
      <StatusBar style='auto' />
    </View>
  )
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center'
  }
})

The <Text>Local storing: {userData}</Text> is allways a unresolved proise object.

I had some success with previous code where console.log(userData) did actually produce the wanted value but it is still not useable inside <Text>. I just dont get it.

Thank you in advance and please keep in mind I’m new to react native.

EDIT: latest attemt:

import { StatusBar } from 'expo-status-bar'
import React, { useState, useEffect } from 'react'
import { StyleSheet, Text, View } from 'react-native'
import { Button, Input } from 'react-native-elements'
import Icon from 'react-native-vector-icons/FontAwesome'
import AsyncStorage from '@react-native-async-storage/async-storage'

export default async function App () {
  let [userData, setUserData] = useState({})

  const storeData = async value => {
    try {
      await AsyncStorage.setItem('@storage_Key', value)
    } catch (e) {
      // saving error
    }
  }

  storeData('test2')


  const getData = async () => {
    try {
      const value = await AsyncStorage.getItem('@storage_Key')
      if(value !== null) {
        console.log(value)
        return value
      }
    } catch(e) {
      // error reading value
    }
  }
  

  userData = await getData()
  console.log(userData)

  return (
    <View style={styles.container}>
      <Text>Local storing: {userData}</Text>
      <StatusBar style='auto' />
    </View>
  )
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center'
  }
})

Now I get for some reason 4 test2 , correct values consoled logged but still get an error:

Error: Objects are not valid as a React child (found: object with keys {_U, _V, _W, _X}). If you meant to render a collection of children, use an array instead.

which is a promise object, and app fails to build.

Answer

Fixed it:

import { StatusBar } from 'expo-status-bar'
import React, { useState, useEffect } from 'react'
import { StyleSheet, Text, View } from 'react-native'
import { Button, Input } from 'react-native-elements'
import Icon from 'react-native-vector-icons/FontAwesome'
import AsyncStorage from '@react-native-async-storage/async-storage'

const storeData = async value => {
  try {
    await AsyncStorage.setItem('@storage_Key', value)
  } catch (e) {
    // saving error
  }
}

storeData('test2')



export default function App () {
  let [userData, setUserData] = useState('')

  useEffect(() => {
    getData()
  }, [])

  const getData = async () => {
    try {
      const value = await AsyncStorage.getItem('@storage_Key')
      if (value !== null) {
        console.log(value)
        setUserData(value)
        userData = value
      }
    } catch (e) {
      // error reading value
    }
  }


  console.log(userData)

  return (
    <View style={styles.container}>
      <Text>Local storing: {userData}</Text>
      <StatusBar style='auto' />
    </View>
  )
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'center'
  }
})
  • there shouldn’t have been async in export default function App () {

  • getData() get data should have been iniciated inside useEffect

    useEffect(() => { storeData(‘test2’) getData() }, [])

  • I have also set the state inside getData()

    userData = value