I'm having this table view in React where I fetch an array from API and display it. When the user types something on the table search box, I'm trying to clear the current state array and render the completely new result. But for some reason, the result keeps getting appended to the current set of results.
Here's my code:
const Layout = () => {
var infiniteScrollTimeout = true;
const [apiList, setapiList] = useState([]);
//invoked from child.
const search = (searchParameter) => {
//Clearing the apiList to load new one but the console log after setApiList still logs the old list
setapiList([]); // tried setApiList([...[]]), copying the apiList to another var and emptying it and then setting it too.
console.log(apiList); //logs the old one.
loadApiResults(searchParameter);
};
let url =
AppConfig.api_url + (searchParameter || "");
const loadApiResults = async (searchParameter) => {
let response = await fetch(url + formurlencoded(requestObject), {
method: "get",
headers: headers,
});
let ApiResult = await response.json(); // read response body and parse as JSON
if (ApiResult.status == true) {
//Set the url for next fetch when user scrolls to bottom.
url = ApiResult.next_page_url + (searchParameter || "");
let data;
data = ApiResult.data;
setapiList([...data]);
}
}
useEffect(() => {
loadApiResults();
document.getElementById("myscroll").addEventListener("scroll", () => {
if (
document.getElementById("myscroll").scrollTop +
document.getElementById("myscroll").clientHeight >=
document.getElementById("myscroll").scrollHeight - 10
) {
if (infiniteScrollTimeout == true) {
console.log("END OF PAGE");
loadApiResults();
infiniteScrollTimeout = false;
setTimeout(() => {
infiniteScrollTimeout = true;
}, 1000);
}
}
});
}, []);
return (
<ContentContainer>
<Table
...
/>
</ContentContainer>
);
};
export default Layout;
What am I doing wrong?
UPDATE: I do see a brief moment of the state being reset, on calling the loadApiResult again after resetting the state. The old state comes back. If I remove the call to loadApiResult, the table render stays empty.
add apiList in array as the second parameter in useEffect
You need to use the dependencies feature in your useEffect function
const [searchParameter, setSearchParameter] = useState("");
... mode code ...
useEffect(() => {
loadApiResults();
... more code ...
}, [searchParameter]);
useEffect will automatically trigger whenever the value of searchParameter changes, assuming your input uses setSearchParameter on change
Related
In my React app I am showing a banner yes or no, based on React state and some values set in localStorage.
After close button is clicked, it's state showBanner is saved to localStorage and doesn't show the banner anymore
After 2 times using a page url in the React app with query param redirect=my-site it doesn't show the banner anymore:
import queryString from 'query-string';
const location = useLocation();
const queryParams = queryString.parse(location.search);
const [showBanner, setShowBanner] = useState(true);
const handleClick = () => {
setShowBanner(false);
localStorage.removeItem('redirect');
};
const hasQp = queryString
.stringify(queryParams)
.includes('redirect=my-site');
const initialCount = () => {
if (typeof window !== 'undefined' && hasQp) {
return Number(localStorage.getItem('redirect')) || 0;
}
return null;
};
const [count, setCount] = useState(initialCount);
const show = showBanner && hasQp && count! < 3;
useEffect(() => {
const data = localStorage.getItem('my-banner');
if (data !== null) {
setShowBanner(JSON.parse(data));
}
}, []);
useEffect(() => {
localStorage.setItem('my-banner', JSON.stringify(showBanner));
}, [showBanner]);
useEffect(() => {
let pageView = count;
if (pageView === 0) {
pageView = 1;
} else {
pageView = Number(pageView) + 1;
}
if (hasQp && showBanner === true) {
localStorage.setItem('redirect', String(pageView));
setCount(pageView);
}
}, []);
This is working fine (when you see some good code improvements let me know :) ).
But as soon the user clicks the close button I don't want the localStorage item redirect no longer appears. Now after refreshing the page it appears again.
How do i get this to work?
If this is executing when the page loads:
localStorage.setItem('redirect', String(pageView));
Then that means this is true:
if (hasQp && showBanner === true)
The hasQp value is true, which means this is true:
const hasQp = queryString
.stringify(queryParams)
.includes('redirect=my-site');
And showBanner is true because it's always initialized to true:
const [showBanner, setShowBanner] = useState(true);
It's not 100% clear to me why you need this state value, but you could try initializing it to false by default:
const [showBanner, setShowBanner] = useState(false);
But more to the point, I don't think you need this state value at all. It's basically a duplicate of data that's in localStorage. But since both state and localStorage are always available to you, I don't see a reason to duplicate data between them.
Remove that state value entirely and just use localStorage. An example of checking the value directly might be:
if (hasQp && JSON.parse(localStorage.getItem('my-banner')))
Which of course could be refactored to reduce code. For example, consider a helper function to get the value:
const showBanner = () => {
const data = localStorage.getItem('my-banner') ?? false;
if (data) {
return JSON.parse(data);
}
};
Then the check could be:
if (hasQp && showBanner())
There are likely a variety of ways to refactor the code, but overall the point is to not duplicate data. In thie case a value is being stored in localStorage instead of React state because it needs to persist across page loads. Just keep that value in localStorage and use it from there.
I am having a problem with sessionStorage; in particular, I want the id of the ads to be saved in the session where the user puts the like on that particular favorite article.
However, I note that the array of objects that is returned contains the ids starting with single quotes, as shown below:
['', '1', '7']
but I want '1' to be shown to me directly.
While if I go into the sessionStorage I notice that like is shown as:
,1,7
ie with the leading comma, but I want it to start with the number directly.
How can I fix this?
function likeAnnunci(){
let likeBtn = document.querySelectorAll('.like');
likeBtn.forEach(btn => {
btn.addEventListener('click', function(){
let id = btn.getAttribute('ann-id');
//sessionStorage.setItem('like', [])
let storage = sessionStorage.getItem('like').split(',');
//console.log(storage);
if(storage.includes(id)){
storage = storage.filter(id_a => id_a != id);
} else {
storage.push(id);
}
sessionStorage.setItem('like', storage)
console.log(sessionStorage.getItem('like').split(','));
btn.classList.toggle('fas');
btn.classList.toggle('far');
btn.classList.toggle('tx-main');
})
})
};
function setLike(id){
if(sessionStorage.getItem('like')){
let storage = sessionStorage.getItem('like').split(',');
if(storage.includes(id.toString())){
return `fas`
} else {
return `far`
}
} else {
sessionStorage.setItem('like', '');
return`far`;
}
}
The main issue you're having is that you're splitting on a , instead of using JSON.parse().
Also, you've got some other code issues and logical errors.
Solution:
function likeAnnunci() {
const likeBtn = document.querySelectorAll('.like');
likeBtn.forEach((btn) => {
btn.addEventListener('click', function () {
let id = btn.getAttribute('ann-id');
//sessionStorage.setItem('like', [])
let storage = JSON.parse(sessionStorage.getItem('like') || '[]');
//console.log(storage);
if (!storage.includes(id)) {
storage.push(id);
}
sessionStorage.setItem('like', JSON.stringify(storage));
console.log(JSON.parse(sessionStorage.getItem('like')));
btn.classList.toggle('fas');
btn.classList.toggle('far');
btn.classList.toggle('tx-main');
});
});
}
More modular and optimal solution:
const likeBtns = document.querySelectorAll('.like');
// If there is no previous array stored, initialize it as an empty array
const initLikesStore = () => {
if (!sessionStorage.getItem('likes')) sessionStorage.setItem('likes', JSON.stringify([]));
};
// Get the item from sessionStorage and parse it into an array
const grabLikesStore = () => JSON.parse(sessionStorage.getItem('likes'));
// Set a new value for the likesStore, automatically serializing the value into a string
const setLikesStore = (array) => sessionStorage.setItem('likes', JSON.stringify(array));
// Pass in a value.
const addToLikesStore = (value) => {
// Grab the current likes state
const pulled = grabStorage();
// If the value is already there, do nothing
if (pulled.includes(value)) return;
// Otherwise, add the value and set the new array
// of the likesStore
storage.push(value);
setLikesStore(pulled);
};
const likeAnnunci = (e) => {
// Grab the ID from the button clicked
const id = e.target.getAttribute('ann-id');
// Pass the ID to be handled by the logic in the
// function above.
addToLikesStore(id);
console.log(grabLikesStore());
btn.classList.toggle('fas');
btn.classList.toggle('far');
btn.classList.toggle('tx-main');
};
// When the dom content loads, initialize the likesStore and
// add all the button event listeners
window.addEventListener('DOMContentLoaded', () => {
initLikesStore();
likeBtns.forEach((btn) => btn.addEventListener('click', likeAnnunci));
});
I am trying to render an array of IP Addresses, after pushing each IP to an empty array. Once the array has been populated, I am able to see it correctly in the console, but for some reason, it refuses to show up on screen despite mapping it.
Variables:
var ipList = [];
let key = 0;
const [subnet, setSubnet] = useState("");
This is the first useEffect which is supposed to trigger immediately when the component mounts. This is working fine.
useEffect(() => {
const callNativeCode = async () => {
await ConnectedDevices.displayConnectedDevices( (arrayResponse) => {setArray(arrayResponse), console.log("FIRST NATIVE CALL" + arr)}, (error) => {console.log(error)} );
}
callNativeCode();
},[])
This is the second useEffect which is supposed to populate the empty array with pingable IPs as soon as we get the subnet from the native java code. Also working fine and I get the array as I need it to be.
useEffect(() => {
const ipLoop = async () => {
if( subnet != "")
{
for(let i = 1; i<=254; i++)
{
let ipAddress = subnet + "." + i;
try{
const ip = await Ping.start(ipAddress, {timeout: 100});
const { receivedNetworkSpeed,sendNetworkSpeed,receivedNetworkTotal,sendNetworkTotal } = await Ping.getTrafficStats(ipAddress, {timeout:1000});
console.log(ipAddress + " Network Stats: " + receivedNetworkSpeed,sendNetworkSpeed,receivedNetworkTotal,sendNetworkTotal);
key = i;
ipList.push(key , ipAddress);
}
catch(error)
{
console.log(i + " Error Code: " + error.code + " ," + error.message)
}
}
renderIPList();
}
}
ipLoop();
},[subnet]);
And this is the render function that is supposed to display the array on screen. The log is working fine and I can see the array as intended. It just refuses to render.
const renderIPList = () => {
console.log("RENDERING IPS: ", ipList);
return ipList.map((items,index) => {
return (
<View key={index}>
<Text>{items}</Text>
</View>
);
});
};
Thank you in advance for your help.
Change your ipList to be derived from useState like this:
const [ipList, setIpList] = useState([]);
and use the setIpList in your useEffect
and don't call renderIpList() as a function from useEffect that should be in the component return statement.
So, the useEffect should update the state, and then the component renders the state.
I have a component in which I set my state from the passed parameters to the component
function ChatList({ bookingList, session, setActiveChat, setBookingList, socket }){
const [activeList, setActiveList] = useState(bookingList);
const [defaultList, setDefaultList] = useState(bookingList);
I set the activeList state from the passed params and then on click I update the state in order to show filtered results
const changeTab = (index) => {
if(index === 0){
setActiveList(defaultList);
if(defaultList.length > 0){
setActiveChat(defaultList[0]);
}else{
setActiveChat(null);
}
}else {
let result = bookingList.filter(booking => booking.is_service_provider == false);
setActiveList(result);
if(result.length > 0){
setActiveChat(result[0]);
}else{
setActiveChat(null);
}
}
So ultimately users can filter their chat lists based on the chosen index
And everything works fine, the DOM is updated and if I call the state from a regular function it shows the correct state.
But when I try to update the state from a socket listener I get the original state and not the filtered state
useEffect(() => {
socket.on('notification', (payload) => {
let list_index = activeList.findIndex(obj => obj.id === payload.room);
if(list_index > -1){
let copy = [...activeList];
copy[list_index].latest_message = payload.message;
setActiveList(copy);
}else{
//Handle if user isnt in the correct segment
}
});
},[activeList])
The problem here is the activeList should only have 2 elements after being filtered but in the socket listener it gets the activeList with all the elements as it was before it gets filtered.
I even tested this with a random onclick listener, the onclick function gets the correct state, so why doesn't my socket listener get the updated state?
Thanks
Whenever activeList changes you add a listener but you do not remove the previous handler. It might casue you
So, try using the return of useEffect.
useEffect(() => {
function handler(payload) {....}
socket.on('notification', handler);
return () => socket.off('notification', handler);
}, [activeList]);
In addition when you just want to update the activeList the setter function gets the previous value so you can just use that, and then your effect won't need any dep other than the ref to the setter function.
useEffect(() => {
function handler(payload) {
...
setActiveList((prev) => {
const index = prev.findIndex(obj => obj.id === payload.room);
if (...) return [];
return [];
});
}
socket.on('notification', handler);
return () => socket.off('notification', handler);
}, [setActiveList]);
The problem is that every time I click on an element with a state things appear twice. For example if i click on a button and the result of clicking would be to output something in the console, it would output 2 times. However in this case, whenever I click a function is executed twice.
The code:
const getfiles = async () => {
let a = await documentSpecifics;
for(let i = 0; i < a.length; i++) {
var wrt = document.querySelectorAll("#writeto");
var fd = document.querySelector('.filtered-docs');
var newResultEl = document.createElement('div');
var writeToEl = document.createElement('p');
newResultEl.classList.add("result");
writeToEl.id = "writeto";
newResultEl.appendChild(writeToEl);
fd.appendChild(newResultEl);
listOfNodes.push(writeToEl);
listOfContainers.push(newResultEl);
wrt[i].textContent = a[i].data.documentName;
}
}
The code here is supposed to create a new div element with a paragraph tag and getting data from firebase firestore, will write to the p tag the data. Now if there are for example 9 documents in firestore and i click a button then 9 more divs will be replicated. Now in total there are 18 divs and only 9 containing actual data while the rest are just blank. It continues to create 9 more divs every click.
I'm also aware of React.Strictmode doing this for some debugging but I made sure to take it out and still got the same results.
Firebase code:
//put data in firebase
createFileToDb = () => {
var docName = document.getElementById("title-custom").value; //get values
var specifiedWidth = document.getElementById("doc-width").value;
var specifiedHeight = document.getElementById("doc-height").value;
var colorType = document.getElementById("select-color").value;
parseInt(specifiedWidth); //transform strings to integers
parseInt(specifiedHeight);
firebase.firestore().collection("documents")
.doc(firebase.auth().currentUser.uid)
.collection("userDocs")
.add({
documentName: docName,
width: Number(specifiedWidth), //firebase-firestore method for converting the type of value in the firestore databse
height: Number(specifiedHeight),
docColorType: colorType,
creation: firebase.firestore.FieldValue.serverTimestamp() // it is possible that this is necessary in order to use "orderBy" when getting data
}).then(() => {
console.log("file in database");
}).catch(() => {
console.log("failed");
})
}
//get data
GetData = () => {
return firebase.firestore()
.collection("documents")
.doc(firebase.auth().currentUser.uid)
.collection("userDocs")
.orderBy("creation", "asc")
.get()
.then((doc) => {
let custom = doc.docs.map((document) => {
var data = document.data();
var id = document.id;
return { id, data }
})
return custom;
}).catch((err) => {console.error(err)});
}
waitForData = async () => {
let result = await this.GetData();
return result;
}
//in render
let documentSpecifics = this.waitForData().then((response) => response)
.then((u) => {
if(u.length > 0) {
for(let i = 0; i < u.length; i++) {
try {
//
} catch(error) {
console.log(error);
}
}
}
return u;
});
Edit: firebase auth is functioning fine so i dont think it has anything to do with the problem
Edit: This is all in a class component
Edit: Clicking a button calls the function createFileToDb
I think that i found the answer to my problem.
Basically, since this is a class component I took things out of the render and put some console.log statements to see what was happening. what i noticed is that it logs twice in render but not outside of it. So i took the functions out.
Here is the code that seems to fix my issue:
contain = () => {
const documentSpecifics = this.waitForData().then((response) => {
var wrt = document.getElementsByClassName('writeto');
for(let i = 0; i < response.length; i++) {
this.setNewFile();
wrt[i].textContent = response[i].data.documentName;
}
return response;
})
this.setState({
docs: documentSpecifics,
docDisplayType: !this.state.docDisplayType
})
}
As for creating elements i put them in a function so i coud reuse it:
setNewFile = () => {
const wrt = document.querySelector(".writeto");
const fd = document.querySelector("#filtered-docs");
var newResultEl = document.createElement('div');
newResultEl.classList.add("result");
var wrtEl = document.createElement('p');
wrtEl.classList.add("writeto");
fd.appendChild(newResultEl);
newResultEl.appendChild(wrtEl);
}
The firebase and firestore code remains the same.
the functions are called through elements in the return using onClick.