react native- json parsing (cant parse json object in my code) - json

Question

Here is my code. In this I got x but when I try to parsing x for getting object of x 'isloggedin' it gives error. what should I do wrong tell me if you understand my problem.
componentDidMount() {
this.onLoad();
}
onLoad = async () => {
try {
var walletdata = await AsyncStorage.getItem('wallet');
this.setState({x: JSON.parse(walletdata)})
this.setState({y: JSON.stringify(this.state.x)})
console.log("output: "+ this.state.y);
console.log("output y:"+JSON.parse(this.state.y.isloggedIn));
}catch(error){
console.log("error: "+error);
}
}
error: SyntaxError: JSON Parse error: Unexpected identifier "undefined"

Answer 1

Probably is because 'wallet' key has undefined value in the caché storage. You should check first the value (right after getting the item from the storage) and if it's undefined then you have to set it first.

Answer 2

Probably you need to wait for the first setState function to finish, So that you can get access to it in second call.
In short, It will take some time for setting your value in State and you are trying to access it before updating the state. So try to access the values in the callback of setState function.
Instead of this,
this.setState({x: JSON.parse(walletdata)})
this.setState({y: JSON.stringify(this.state.x)})
console.log("output: "+ this.state.y);
console.log("output y:"+JSON.parse(this.state.y.isloggedIn));
You can use this:
this.setState({x: JSON.parse(walletdata),y: JSON.stringify(walletdata.x)},()=>{
console.log("output: "+ this.state.y);
console.log("output y:"+JSON.parse(this.state.y.isloggedIn));
});

Answer 3

I have solved my problem. Thank you for your answers. below is how could I solved my question.
try {
var walletdata = await AsyncStorage.getItem('wallet');
this.setState({wallet: JSON.stringify(JSON.parse(walletdata))})
this.setState({isLoggedin:JSON.parse
(this.state.wallet).isLoggedin});
console.log(this.state.isLoggedin);
}catch(error){
console.log("error: "+error);
}