React-native : how to check if it's the user's first connection? - react-native

Question

I 'm new to react-native and I would like to set up my first page of the app with
1- The user never logged in the app, I 'll present the app with some slides + go to signup page
2 -The user is already in => directly go to the user page
3 -The user is already in but the id is not correct
Can you guide me through it ?
For the first point I really don't know how to check if the user exist in my db
For the second and third points I thought I'd try :
onPressLogin(){
fetch('linktomyAPI',{
method: 'POST',
headers:{
'Content-Type' : 'application/json',
'Accept':'application/json'
},
body: JSON.stringify({
username:this.state.username,
password: this.state.password,
})
})
.then(response => response.json())
.then((responseData) =>{
if(responseData.error !== 1){ // verify the success case, as you didn't provide the success case i am using the error code
this.setState({ // its recommended you verify the json before setting it to state.
userdetail: responseData,
})
setTimeout(() => {
Actions.Authentication();
}, 2300);
AsyncStorage.setItem('username', this.state.username); // its setItem not saveitem.
} else {
console.log(responseData);
Alert.alert(JSON.stringify(responseData)); // Alerts doesn't allow arrays or JSONs, so stringify them to view in Alerts
}
}).catch((error) => {
// handle catch
console.log("error:"+JSON.stringify(error));
});
}
Do you think I can do this way, is that relevant?
Thanks for taking the time to answer me. I'm really new so I need help and explanations. Thanks !!! :)

Answer 1

you can use the UserInfo to do. firstly, you have saved the user info in memory use Session js and in the device local file use AsyncStore. you already do it use the AsyncStore.
firstly save the user info into Session,the Session structure is:{id:"dd333",name:"john"},
...
setTimeout(() => {
Actions.Authentication();
}, 2300);
Session.id = res.id;
Session.name = res.name;
AsyncStorage.setItem('userinfo', Json.stringfy(res));
then you can show diffent page and condition.
// in the component which you want compoentDidMount
componentDidMount() {
// here you can try to get it from AsyncStore if the Session is null.
// then hanle it as the followng
if(Session.id == ""){
//default it is "", it means the user does not login
} else if(Session.id != "222"){
// the user id is not correct
} else {
// here is the user login and id is correct
}
}