I have a problem with one of my components. The problem I think I have is that my component executes before my user context stores the currentUser. My code only works when doing a hot reload.
The watchlist component gets all the values from the watchlist array where the document matches the currentUser.uid.
UserContext.js:
const [currentUser, setCurrentUser] = useState(null)
const [watchlist, setWatchlist] = useState(null)
useEffect(() => {
const unsubscribe = auth.onAuthStateChanged(user => {
setCurrentUser(user)
})
return unsubscribe
}, [])
const getWatchlist = async () => {
const userRef = await getDoc(doc(db, 'users', currentUser.uid))
setWatchlist(userRef.data().watchlist)
console.log(userRef.data().watchlist)
}
These values are the ids of objects I then GET from an API, these are then pushed to the watchlistData array.
CryptoContext.js
export const getWatchlistData = async (list) => {
const watchlistData = []
for (const item of list) {
const result = await axios.get(
`${coingecko}/coins/${item}`
)
watchlistData.push(result.data)
}
return watchlistData
}
And this is how my Watchlist component code currently looks.
WatchlistItems.jsx
const { watchlist, getWatchlist, currentUser } = useContext(UserContext)
const { dispatch } = useContext(CryptoContext)
useEffect(() => {
if (currentUser) {
dispatch({type: 'SET_LOADING'})
const getWatchlistDataFromAPI = async () => {
await getWatchlist()
const watchlistData = await getWatchlistData(watchlist)
dispatch({type: 'GET_WATCHLIST', payload: watchlistData})
console.log(watchlistData)
}
getWatchlistDataFromAPI()
}
}, [currentUser])
If I refresh the page I get "Uncaught (in promise) TypeError: the list is not iterable", but if I do a hot reload, watchlist, and watchlistData both console.log with the correct data.
This is my first post and so please let me know if I've left anything out.
Thank you in advance for any help :)
Related
I'm using firestore to store posts each post could have simple properties such as {title: 'hi', comment: true} I'm able to easily fetch the user's specific posts since my collection structure looks like this: posts/user.id/post/post.name so an example will be posts/1234sofa/post/cool day
with this way of structuring, I'm able to easily fetch data for the user, but I'm having trouble with two things how do I fetch and display all posts for my main feed, and what's the most effective way of doing this? here is my current function for fetching user-specific data:
const submitpost = async () => {
try {
const collectionRef=collection(db,`posts`,user.uid.toString(),'post')
await addDoc(collectionRef, {
post: post,
timestamp: serverTimestamp(),
canComment: switchValue,
user: user.uid,
avatar: user.photoURL,
username: user.displayName,
});
toast({ title: "posted", status: "success", duration: 2000 });
} catch (error) {
console.log(error);
}
};
this specific function creates a structure like this in firebase posts are just takes and take is singular post respectively I just changed the name so its easier to understand:
now here is how im fetching the data for my spefic user:
const [user] = useAuthState(auth);
const [takes, settakes] = useState([]);
const getData = async () => {
// if user is present run function
if (user) {
// const docRef = doc(db, "users", user.uid);
// const collectionRef = collection(docRef, "takes");
// const querySnapshot = await getDocs(collectionRef);
try {
const docRef = doc(db, "posts", user.uid);
const collectionRef = collection(db,'posts',user.uid,'takes');
const querySnapshot = await getDocs(collectionRef);
const data = querySnapshot.docs.map((d) => ({
id: d.id,
...d.data(),
}));
settakes(data);
} catch (error) {
console.log(error);
}
//
}
};
here is the function that doesn't work when fetching all data for main feed:
const [user]=useAuthState(auth)
const [allfeed, setallfeed] = useState([])
const getData = async () => {
if(user){
const collectionRef = collection(db, "posts");
const querySnapshot = await getDocs(collectionRef);
const data = querySnapshot.docs.map((d) => ({
id: d.id,
...d.data(),
}));
// get data from firebase
setallfeed(data)
}
}
useEffect(() => {
getData()
console.log('ran');
console.log(allfeed);
// rerun when user is present
}, [user]);
when I console log the allfeed it returns an empty array so my main problem is how to do I get all the data from the posts collection meaning posts/userid/post/post.title I need to get these for every user. and secondly is there a more efficient way to structure my data?
I would suggest using the onSnapshot() method if you want realtime updates from a collection or a specific document.
setState() does not make changes directly to the state object. It just creates queues for React core to update the state object of a React component. If you add the state to the useEffect, it compares the two objects, and since they have a different reference, it once again fetches the items and sets the new items object to the state. The state updates then triggers a re-render in the component. And on, and on, and on...
If you just want to log your data into your console then you must use a temporary variable rather than using setState:
const getData = async () => {
if(user){
// Using `getDocs`
const collectionRef = collection(db, "posts");
const querySnapshot = await getDocs(collectionRef);
const data = querySnapshot.docs.map((d) => ({
id: d.id,
...d.data(),
}));
console.log(data)
// ============================================= //
// Using `onSnapshot()`
const q = query(collection(db, "posts"));
const unsubscribe = onSnapshot(q, (querySnapshot) => {
const data = querySnapshot.docs.map(d => ({
id: d.id,
...d.data()
}))
console.log(data)
});
}
}
useEffect(() => {
getData();
}, []);
You could also use multiple useEffect() to get the updated state of the object:
const getData = async () => {
if(user){
// Using `getDocs`
const collectionRef = collection(db, "posts");
const querySnapshot = await getDocs(collectionRef);
const data = querySnapshot.docs.map((d) => ({
id: d.id,
...d.data(),
}));
setallfeed(data)
// ============================================= //
// Using `onSnapshot()`
const q = query(collection(db, "posts"));
const unsubscribe = onSnapshot(q, (querySnapshot) => {
const data = querySnapshot.docs.map(d => ({
id: d.id,
...d.data()
}))
setallfeed(data)
});
}
}
useEffect(() => {
getData();
}, [])
useEffect(() => {
console.log(allfeed);
}, [allfeed]);
If you want to render it to the component then you should call the state in the component and map the data into it. Take a look at the sample code below:
const getData = async () => {
if(user){
// Using `getDocs`
const collectionRef = collection(db, "posts");
const querySnapshot = await getDocs(collectionRef);
const data = querySnapshot.docs.map((d) => ({
id: d.id,
...d.data(),
}));
setallfeed(data)
// ============================================= //
// Using `onSnapshot()`
const q = query(collection(db, "posts"));
const unsubscribe = onSnapshot(q, (querySnapshot) => {
const data = querySnapshot.docs.map(d => ({
id: d.id,
...d.data()
}))
setallfeed(data)
});
}
}
useEffect(() => {
getData()
}, []);
return (
<div>
<p>SomeData: <p/>
{items.map((item) => (
<p key={item.id}>{item.fieldname}</p>
))}
</div>
);
For more information you may checkout these documentations:
Get data with Cloud Firestore
Get realtime updates with Cloud Firestore
I am building a website using nextjs and axios. Users can apply to become a member and then be approved by admins. In the admin dashboard I initially load the users and the unapproved users and display them in a list.
When an admin clicks on a button the unapproved user should be approved. The functionality works. The only aspect I can't figure out is how to update the state.
Here is my code:
const AdminIndex = () => {
const [users, setUsers] = useState([])
const [unapprovedUsers, setUnapprovedUsers] = useState([])
useEffect(() => {
loadUnapprovedUsers()
loadUsers()
}, [])
const loadUnapprovedUsers = async () => {
const { data } = await axios.get('/api/admin/unapprovedUsers')
setUnapprovedUsers(data)
}
const loadUsers = async () => {
const { data } = await axios.get('/api/admin/users')
setUsers(data)
}
const approveUnapprovedUser = async (email) => {
try {
const { data } = await axios.put(
`/api/admin/approveUnapprovedUser/${email}`
)
setUnapprovedUsers([]) // only remove the approved user
setUsers(...data) // include the approved user into the array
} catch (err) {
console.log(err)
}
}
}
I am trying to remove the approved user from the unapprovedUsers array and try to add the user to the users array, hence updating the UI. The response returned by axios is an object, which doesn't make things easier.
I would be very thankful for any kind of help!
Just try to filter the unapprovedUsers with the users that don't have that email, also add the approved user to users state
const AdminIndex = () => {
const [users, setUsers] = useState([])
const [unapprovedUsers, setUnapprovedUsers] = useState([])
useEffect(() => {
loadUnapprovedUsers()
loadUsers()
}, [])
const loadUnapprovedUsers = async () => {
const { data } = await axios.get('/api/admin/unapprovedUsers')
setUnapprovedUsers(data)
}
const loadUsers = async () => {
const { data } = await axios.get('/api/admin/users')
setUsers(data)
}
const approveUnapprovedUser = async (email) => {
try {
const { data } = await axios.put(
`/api/admin/approveUnapprovedUser/${email}`
)
setUnapprovedUsers(prev => prev.filter(user => user.email !== email)) // only remove the approved user
setUsers(prev => [...prev, data]) // include the approved user into the array
} catch (err) {
console.log(err)
}
}
}
I have a problem concern filter in JavaScript can't working.
I'm not sure may because API using long time for response
My code :
const getDataAll = () =>{
const [machines, setMachines] = useState([])
const getMc = async () =>{
try {
const resMc = await axios.get("My API")
setMachines(resMc.data)
} catch (err) {
console.error(err.message)
}
useEffect(()=>{
getMc()
},[])
const sumData = () =>{
const filterName = machines.data.filter((el) => el.name == "v10turbo")
}
}
Filter have show this alert in some time.
And i see time show in browser for API response around 8-9 second follow image below
I'm not sure if I got it right.
if right please help me with to solve this problem
The code itself is correct. But when your component renders, there is no data yet, useeffect works after rerender. You need a loading state:
const getDataAll = () =>{
const [machines, setMachines] = useState([]);
const [loading, setLoading] = useState(true);
const getMc = async () =>{
try {
const resMc = await axios.get("My API")
setMachines(resMc.data)
setLoading(false);
} catch (err) {
console.error(err.message)
}
finally {
setLoading(false);
}
}
useEffect(()=>{
getMc()
},[])
const sumData = () =>{
const filterName = machines.data.filter((el) => item.name == "v10turbo")
}
}
if(loading) {
return<p>Loading...</p>
}
This should fix it.
I not sure, but this can be helpful
const sumData = useCallback(() =>{
const filterName = machines.data?.filter((el) => item.name == "v10turbo")
}, [machines]);
I am using fetch to get data from API. I am using useEffect for page to stop rerender. But its not working
const [load, setLoad] = useState(false);
if (load) {
return <h2>Progress</h2>;
}
const fetchPicth = async () => {
setLoad(true);
const response = await fetch(url);
const data = await response.json();
setPicth(data.pink);
};
useEffect(() => {
setLoad(false);
}, [fetchPicth]);
This can be solved using 2 approaches
Pass state in dependency array of useEffect
const [picth, setPicth] = useState([]); // Initial state
useEffect(() => {
if (picth && picth.length !== 0) { // Checks if data exists and length
//is greater than 0
setLoad(false); // Set Loading to false
}
}, [picth]);
const fetchPicth = async () => {
setLoad(true);
const response = await fetch(url);
const data = await response.json();
setPicth(data.pink);
};
Check for the length, display Progress if there is no data. Display if data is present.
{picth.length === 0 && <div>Progress</div>}
{picth.length > 0 && (
<div>
{picth.map((book, index) => {
return (
<YourComponent></YourComponent>
);
})}
Remove the fetchPicth from the dependency array. If you'd like to set load to false you can do it like this:
const [load, setLoad] = useState(false);
if (load) {
return <h2>Progress</h2>;
}
const fetchPicth = async () => {
setLoad(true);
const response = await fetch(url);
const data = await response.json();
setPicth(data.pink);
setLoad(false)
};
useEffect(() => {
fetchPicth();
}, []);
Using the code above will only fetch the data from the API only once i.e; when the component is mounted.
I am doing a React.js project. I am trying to pull data from an API that has multiple endpoints. I am having issues with creating a function that pulls all the data at once without having to do every endpoint separetly. The console.log gives an empty array and nothing gets display. The props 'films' is data from the parent and works fine. It is also from another enpoint of the same API. This is the code:
import { useEffect, useState } from "react";
import styles from './MovieDetail.module.css';
const MovieDetail = ({films}) => {
const [results, setResults] = useState([]);
const fetchApis = async () => {
const peopleApiCall = await fetch('https://www.swapi.tech/api/people/');
const planetsApiCall = await fetch('https://www.swapi.tech/api/planets/');
const starshipsApiCall = await fetch('https://www.swapi.tech/api/starships/');
const vehicleApiCall = await fetch('https://www.swapi.tech/api/vehicles/');
const speciesApiCall = await fetch('https://www.swapi.tech/api/species/');
const json = await [peopleApiCall, planetsApiCall, starshipsApiCall, vehicleApiCall, speciesApiCall].json();
setResults(json.results)
}
useEffect(() => {
fetchApis();
}, [])
console.log('results of fetchApis', results)
return (
<div className={styles.card}>
<div className={styles.container}>
<h1>{films.properties.title}</h1>
<h2>{results.people.name}</h2>
<p>{results.planets.name}</p>
</div>
</div>
);
}
export default MovieDetail;
UPDATE
I just added the post of Phil to the code and I uploaded to a codesanbox
You want to fetch and then retrieve the JSON stream from each request.
Something like this
const urls = {
people: "https://www.swapi.tech/api/people/",
planets: "https://www.swapi.tech/api/planets/",
starships: "https://www.swapi.tech/api/starships/",
vehicles: "https://www.swapi.tech/api/vehicles/",
species: "https://www.swapi.tech/api/species/"
}
// ...
const [results, setResults] = useState({});
const fetchApis = async () => {
try {
const responses = await Promise.all(Object.entries(urls).map(async ([ key, url ]) => {
const res = await fetch(url)
return [ key, (await res.json()).results ]
}))
return Object.fromEntries(responses)
} catch (err) {
console.error(err)
}
}
useEffect(() => {
fetchApis().then(setResults)
}, [])
Each URL will resolve to an array like...
[ "people", [{ uid: ... }] ]
Once all these resolve, they will become an object (via Object.fromEntries()) like
{
people: [{uid: ... }],
planets: [ ... ],
// ...
}
Take note that each property is an array so you'd need something like
<h2>{results.people[0].name}</h2>
or a loop.