Async Storage / Secure Store help for React Native - react-native

I'm doing a test app to learn react native, and I'm trying to use secure store (a bit like async storage) to store my individual goals and save them. So far it's working, however when I refresh the app only the last goal I entered gets loaded.
Where am I going wrong here? In my console log the full array is shown with both the old and the new ones I add, then I refresh and I only have one left.
const [goals, setGoals] = useState([])
const addGoal = async (goal) => {
try{
const goalJson = JSON.stringify({text: goal, id:`${Math.random()}`, todos:[], date: Date.now(), percentage:0})
await SecureStore.setItemAsync("Goal", goalJson)
load()
}
catch (err) {alert(err)}
}
const load = async() => {
try {
const goalValue = await SecureStore.getItemAsync("Goal")
const parsed = JSON.parse(goalValue)
if(goals !== null) {
setGoals([...goals, parsed])
console.log(goals)
}
}catch (err) {alert(err)}
}
useEffect(()=> {
load()
},[])

SecureStore is like a key-value database, so currently you're always writing to the same key Goal and your addGoal function is erasing the previous value with goalJson content.
Instead, load once the goals from storage, then update the goals state when a new goal is added, and write them all to on storage each time goals value is updated.
This how effects works, by "reacting" to a change of value. This is just a little bit more complicated because of SecureStorage async functions.
Here is my (untested) improved code. I renamed the storage key from Goal to Goals.
const [goals, setGoals] = useState([])
const [loaded, setLoaded] = useState(false)
useEffect(()=> {
async function load() {
try {
const goalsValue = await SecureStore.getItemAsync("Goals")
const goalsParsed = JSON.parse(goalsValue)
if (goalsParsed !== null) {
setGoals(goalsParsed)
}
setLoaded(true)
} catch (err) { alert(err) }
}
load()
}, []) // load only when component mount
const addGoal = (text) => {
const goal = { text, id:`${Math.random()}`, todos:[],
date: Date.now(), percentage:0 }
setGoals([...goals, goal])
})
useEffect(() => {
async function saveGoals() {
try {
// save all goals to storage
const goalsJson = JSON.stringify(goals)
await SecureStore.setItemAsync("Goals", goalsJson)
}
catch (err) {alert(err)}
}
if (loaded) { // don't save before saved goals were loaded
saveGoals();
}
}, [goals, loaded]) // run the effect each time goals is changed

Related

How to call API inside expo SplashScreen?

I'm new in react native so I can't figure out how to add an API call inside SplashScreen in react -native app. The context - I'm building a react-native app expo, which on app load should send API GET request to the backend to get order data, and based on that data I'm either displaying screen A(delivered) or B(order on it's way). I want to add this API call inside the SplashScreen when app still loads so when app is loaded there is no delay in getting API data and displaying screen A/B.
I have a simple useEffect function to call API like this:
const [data, setData] = useState{[]}
useEffect(() => {
const getData = async () => {
try {
const response = await axios.get(url);
if (response.status.code === 200 ) {
setData (response.data) // to save data in useState
}
} else if (response.status.code != 200) {
throw new Error();
}
} catch (error) {
console.log(error);
}
};
getData();
}, []);
and then in the return:
if (data.order.delivered) {
return <ScreenA />
}
else if (!data.order.delivered) {
return <ScreenB />
else {return <ScreenC />}
The issue is that sometimes if API is slow, then after splash screen app has a white screen, or ScreenC can be seen. How can I call API in the splashscreen while app is loading and have a nicer ux?
you can make a custom hook with simple UseState and put it after you've fetched your data
const [loading, setLoading] = useState(true)
...
useEffect(() => {
const getData = async () => {
try {
const response = await axios.get(url);
if (response.status.code === 200 ) {
setData (response.data)
// When data is ready you can trigger loading to false
setLoading(false)
}
...
and After that, you can use a Simple If statement on top of your app.js file
like this
if (!loaded) {
return <LoadingScreen/>; // whetever page you want to show here ;
}
you can use expo expo-splash-screen to achieve this goal:
call this hook on mount...
import * as SplashScreen from 'expo-splash-screen';
const [appIsReady, setAppIsReady] = useState(false);
useEffect(() => {
async function prepare() {
try {
// Keep the splash screen visible while we fetch resources
await SplashScreen.preventAutoHideAsync();
// Pre-load fonts, make any API calls you need to do here
await Font.loadAsync(Entypo.font);
// Artificially delay for two seconds to simulate a slow loading
// experience. Please remove this if you copy and paste the code!
await new Promise(resolve => setTimeout(resolve, 2000));
} catch (e) {
console.warn(e);
} finally {
// Tell the application to render
setAppIsReady(true);
}
}
prepare();
}, []);
you can also check expo doc

How to make pagination work? Async await function in vue.js 3 setup

I was trying to make an app which lists a user's repositories from github using github API, however I'm having a big problem with fetching data from all pages (so far I can only get repos from one page). I tried to fix it by using an async/await function (instead of Promise), but it's also my first time using vue3 and I have no idea how to have a function inside of the setup() method.
The current code is here:
https://github.com/agzpie/user_repos
My try at using async/await, which didn't work:
import ListElement from "./components/ListElement";
import { ref, reactive, toRefs, watchEffect, computed } from "vue";
export default {
name: "App",
components: {
ListElement,
},
setup() {
const name = ref(null);
const userName = ref(null);
const state = reactive({ data: [] });
let success = ref(null);
const userNameValidator = /^[a-z\d](?:[a-z\d]|-(?=[a-z\d])){0,38}$/i;
const split1 = reactive({ spl1: [] });
const split2 = reactive({ spl2: [] });
async function myFetch() {};
/*
* Check for input in the form and then fetch data
*/
watchEffect(() => {
if (!userName.value) return;
if (!userNameValidator.test(userName.value)) {
console.log("Username has invalid characters");
return;
}
let hasNext = false;
state.data = [];
do {
async function myFetch() {
let url = `https://api.github.com/users/${userName.value}/repos?per_page=5`;
let response = await fetch(url);
if (!response.ok) {
success.value = false;
throw new Error(`HTTP error! status: ${response.status}`);
}
success.value = true;
// check response.headers for Link to get next page url
split1.spl1 = response.headers.get("Link").split(",");
let j = 0;
while (j < split1.spl1.length) {
split2.spl2[j] = split1.spl1[j].split(";");
console.log(split2.spl2[j][0]);
console.log(split2.spl2[j][1]);
if (split2.spl2[j][1].includes("next")) {
let urlNext = split2.spl2[j][0].replace(/[<>(\s)*]/g, "");
console.log(urlNext);
url = urlNext;
hasNext = true;
break;
} else {
hasNext = false;
}
j++;
}
// second .then
let myData = await response.json();
state.data.push(...myData);
console.log("data", myData);
name.value = "";
}
myFetch().catch((err) => {
if (err.status == 404) {
console.log("User not found");
} else {
console.log(err.message);
console.log("oh no (internet probably)!");
}
});
} while (hasNext);
});
// Sort list by star count
const orderedList = computed(() => {
if (state.data == 0) {
return [];
}
return [...state.data].sort((a, b) => {
return a.stargazers_count < b.stargazers_count ? 1 : -1;
});
});
return {
myFetch,
success,
isActive: true,
name,
userName,
ListElement,
...toRefs(state),
orderedList,
};
},
};
Any help would be highly appreciated
The call to myFetch() near the end is a call to an async function without an await, so it is effectively going to loop (if hasNext was initialized to true, but it isn't) without waiting for it to complete.
You should probably change that line to await myFetch() and wrap it all with a try/catch block.
I also don't really care for the way you're directly updating state inside the async myFetch call (it could also be doing several of those if it looped) and perhaps it should be returning the data from myFetch instead, and then you can use let result = await myFetch() and then make use of that when it returns.
Also, instead of awaiting myFetch() result, you could not await it but push it onto a requests array and then use await Promise.all(requests) outside the loop and it is one operation to await, all requests running in parallel. In fact, it should probably be await Promise.allSettled(requests) in case one of them fails. See allSettled for more.
But also I wonder why you're reading it paged if the goal is to fetch them all anyway? To reduce load on the server? If that is true, issuing them paged but in parallel would probably increase the load since it will still read and return all the data but require multiple calls.

Simplest way to merge two useState values

I have a react native hook where trips must be updated every time a createdTrips is added to the state:
const [trips, setTrips] = useState([]);
function fetchCreatedTrips() {
try {
API.graphql(graphqlOperation(onCreateTrip)).subscribe({
next: (result) => {
console.log(result);
const updatedTrips = [...trips, result.value.data.onCreateTrip]
setTrips(updatedTrips)
}
})
} catch (err) { console.log(err) }
}
Now, when i first open the screen, it renders all the trips items of the list.
However with the current code, after i create a trip and go back to that screen, it doesn't currently return all the trips + the newly created one, but only one, that is the newly created one. How can i return all the items of the list? Sorry in advance, i'm a beginner.
While setting the new state on your effect you should include the previous values of the trips. You can use the spread operator to do the same.
const createdTrips = [result.value.data.onCreateTrip];
setTrips([...createdTrips, ...trips]);
or better merge the newly created trip in the updateTrips variable and then set it as the state value,
const udpatedTrips = [...trips,result.value.data.onCreateTrip];
setTrips(udpatedTrips);
The problem in your code is you are firing those two methods at the same time and there can be race conditions, so you see random updates on the screen.
Ideally, you need to bring in some consistency in the API calls and the state update. So first fetchTrips()->then->fetchCreatedTrips(). Try the below code wherein I don't update the state immediately in fetchTrips() but rather pass on the results to fetchCreatedTrips() which completes the API call and updates the state together.
const [trips, setTrips] = useState([]);
useEffect(() => {
fetchTrips();
}, [])
async function fetchTrips() {
try {
const tripData = await API.graphql(graphqlOperation(listTrips));
const trips = tripData.data.listTrips.items
fetchCreatedTrips(trips);
} catch (err) { console.log(err) }
}
function fetchCreatedTrips(fetchedTrips) {
try {
API.graphql(graphqlOperation(onCreateTrip)).subscribe({
next: (result) => {
console.log(result);
const updatedTrips = [...fetchedTrips,...updatedTrips];
setTrips(updatedTrips)
}
})
} catch (err) { console.log(err) }
}
PS: Please handle exceptions correctly.

React Native Hooks initializer not taking the correct value

What I am trying to do is sync a list of attendees from an online database, and if the current user is in the list, then disable a button, else enable the button.
I am using react native hook (I am not sure if I am using the term correctly as I am fairly new to react), in order to set the value of disabling the button.
The issue that I am facing is that the value is getting initialized to false, even tho it should clearly get initialized to true.
After adding some logging I made sure that the function is executing correctly and reaching the code where it sets the value to true.
const [buttonDisabled, changeButtonState] = useState( () => {
var database = firebase.database();
var userId = firebase.auth().currentUser.uid;
const dbRef = firebase.database().ref();
var Attendees = [];
var disable = false;
dbRef.child("gameAttendees").child(gameinfo.gameID).get().then((snapshot) => {
if (snapshot.exists()) {
Attendees = snapshot.val().Attendees;
for(var i=0;i<Attendees.length;i++){
if(Attendees[i]==userId){
return true;
}
}
} else {
console.log("no value");
return false;
}
}).catch((error) => {
console.error(error);
});
});
Adding an example of an async mount effect:
const Comp = () => {
const [s, setS] = useState(); // State will be undefined for first n renders
useEffect(() => {
// Call the async function and set the component state some time in the future
someAsyncFunction().then(result => setS(result));
}, []); // An effect with no dependencies will run only once on mount
return </>;
};

React Native - How to see what's stored in AsyncStorage?

I save some items to AsyncStorage in React Native and I am using chrome debugger and iOS simulator.
Without react native, using regular web development localStorage, I was able to see the stored localStorage items under Chrome Debugger > Resources > Local Storage
Any idea how can I view the React Native AsyncStorage stored items?
React Native Debugger has this built in.
Just call showAsyncStorageContentInDev() in the RND console and you'll be able to see a dump of your app's storage.
You can use reactotron i think it has Async Storage explorer ;)
https://github.com/infinitered/reactotron
Following should work,
AsyncStorage.getAllKeys((err, keys) => {
AsyncStorage.multiGet(keys, (error, stores) => {
stores.map((result, i, store) => {
console.log({ [store[i][0]]: store[i][1] });
return true;
});
});
});
I have created a helper method to log all Storage in a single object (more clean to log for example in Reactotron):
import AsyncStorage from '#react-native-community/async-storage';
export function logCurrentStorage() {
AsyncStorage.getAllKeys().then((keyArray) => {
AsyncStorage.multiGet(keyArray).then((keyValArray) => {
let myStorage: any = {};
for (let keyVal of keyValArray) {
myStorage[keyVal[0]] = keyVal[1]
}
console.log('CURRENT STORAGE: ', myStorage);
})
});
}
react native debugger
right click on free space
With bluebird you can do this:
const dumpRaw = () => {
return AsyncStorage.getAllKeys().then(keys => {
return Promise.reduce(keys, (result, key) => {
return AsyncStorage.getItem(key).then(value => {
result[key] = value;
return result;
});
}, {});
});
};
dumpRaw().then(data => console.log(data));
Maybe late, but none of these solutions fit for me.
On android, with Android Studio open file explorer then go to data/data/your_package_name
Inside you should have a folder called database and inside a file RKStorage.
This file is a SQLite3 file so get your favorite SQLite explorer and explore. If you want one this one does the job : DB Browser for SQLite
I did not find Reactotron to have any type of pretty printing enabled and it's also brutally latent so I just wrote a simple function using lodash. You could use underscore too.
Assuming you have a static mapping of all your keys...
const keys = {
key1: 'key1',
key2: 'key2'
}
export function printLocalStorage() {
_.forEach(keys, (k, v) => {
localStore.getAllDataForKey(v).then(tree => {
console.log(k) // Logs key above the object
console.log(tree) // Logs a pretty printed JSON object
})
})
}
It's not performant but it solves the problem.
You can Define function to get all keys by using async and await
getAllkeys = () => {
return new Promise( async (resolve, reject) => {
try {
let keys = await AsyncStorage.getAllKeys();
let items = await AsyncStorage.multiGet(keys)
resolve(items)
} catch (error) {
reject(new Error('Error getting items from AsyncStorage: ' + error.message))
}
});
}
somefunc = async () => {
try {
var items = await getAllkeys();
var someItems = items.filter(function (result, i, item) {
// do filtering stuff
return item;
});
// do something with filtered items
} catch (error) {
// do something with your error
}
}
I have a expo snack that shows this and also performs a "load". So it is useful for doing a dump of the contents and storing it to a file and loading it up later.
Here are they parts.
const keys = await AsyncStorage.getAllKeys();
const stores = await AsyncStorage.multiGet(keys);
const data = stores.reduce(
(acc, row) => ({ ...acc, [row[0]]: row[1] }),
{}
);
// data now contains a JSONable Javascript object that contains all the data
This ammends the data in the AsyncStorage from a JSON string.
// sample is a JSON string
const data = JSON.parse(sample);
const keyValuePairs = Object.entries(data)
.map(([key, value]) => [key, value])
.reduce((acc, row) => [...acc, row], []);
await AsyncStorage.multiSet(keyValuePairs);
import AsyncStorage from "#react-native-async-storage/async-storage";
export const printAsyncStorage = () => {
AsyncStorage.getAllKeys((err, keys) => {
AsyncStorage.multiGet(keys, (error, stores) => {
let asyncStorage = {}
stores.map((result, i, store) => {
asyncStorage[store[i][0]] = store[i][1]
});
console.table(asyncStorage)
});
});
};
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