im builiding a notebloc, so each time I go to the Edit note screen then go back, this warnings appears, heres the code:
when the app runs, the first component that rendes is Notes:
class Notes extends Component {
state = {
onpress: false,
array_notes: [],
selected_notes: [],
update: false,
}
note = "";
note_index = "";
note_number = "";
item_selected = 0;
onpress = false;
componentDidMount() {
const {navigation} = this.props;
this._unsubscribe = navigation.addListener("didFocus", () => this.fetch_notes());
}
componentWillUnmount() {
this._unsubscribe.remove();
}
fetch_notes = async() => { //fetch all the data
const data = await fetch_notes();
if (typeof data != "function") {
this.setState({array_notes: data.array_notes});
}else {
data();
}
}
as you can see, in the ComponentDidmount() I run the function fetch_data to set the data, heres the fetch_data function:
import AsyncStorage from "#react-native-community/async-storage";
export const fetch_notes = async () => {
try {
const data = JSON.parse(await AsyncStorage.getItem("data"));
if (data != null) {
return data;
}else {
return () => alert("with no data");
}
}catch (error) {
alert(error);
}
}
here everything works, because its only fetch the data, now when I go to edit note screen and I edit one of the notes, I need to save it, so when I go back I need to fetch the data again so it will update:
save_changes = async() => {
try {
const data = JSON.parse(await AsyncStorage.getItem("data"));
const index_to_find = this.array_notes.findIndex(obj => obj.note_number === this.note[0].note_number);
const edited_note = this.note.map((note) => {
note.content = this.state.content;
return {...note}
});
this.array_notes.splice(index_to_find, 1, edited_note[0]);
data.array_notes = this.array_notes;
await AsyncStorage.setItem("data", JSON.stringify(data));
}catch(error) {
alert(error);
}
when I get back to Notes screen the function runs and works, the data are updated, but the warning still appears, once I saved the edit note and go back, how can I avoid this?
This warning is thrown when you try to set the state of a component after it has unmounted.
Now, some things to point out here
The navigation flow, from what have you mentioned is like Notes --> Edit Notes --> Notes. Assuming you are using the StackNavigator from react-navigation, the Notes screen will not unmount when you navigate to Edit Notes screen.
The only screen unmounting is Edit Notes when you go back. So you should check the code to verify that you don't have any asynchoronous setState calls in that screen.
P.S : The syntax to remove the focus event listener is to just call the returned function as mentioned here.
So in your Notes screen inside componentWillUnmount it should be
componentWillUnmount() {
this._unsubscribe();
}
you need to use componentWillUnmount() function inside the function which you are unmounting.
You can use conditional rendering for mounting or unmounting any componets.
Related
Im mostly using SWR to get data, however I have a situation that I need to update data. The problem is, I need an indicator that this request is ongoing, something like isLoading flag. In the docs there's a suggestion to use
const isLoading = !data && !error;
But of course when updating (mutating) the data still exists so this flag is always false. The same with isValidating flag:
const { isValidating } = useSWR(...);
This flag does NOT change when mutation is ongoing but only when its done and GET request has started.
Question
Is there a way to know if my PUT is loading? Note: I dont want to use any fields in state because it won't be shared just like SWR data is. Maybe Im doing something wrong with my SWR code?
const fetcher = (url, payload) => axios.post(url, payload).then((res) => res);
// ^^^^^ its POST but it only fetches data
const updater = (url, payload) => axios.put(url, payload).then((res) => res);
// ^^^^^ this one UPDATES the data
const useHook = () => {
const { data, error, mutate, isValidating } = useSWR([getURL, payload], fetcher);
const { mutate: update } = useSWRConfig();
const updateData = () => {
update(getURL, updater(putURL, payload)); // update data
mutate(); // refetch data after update
};
return {
data,
updateData,
isValidating, // true only when fetching data
isLoading: !data && !error, // true only when fetching data
}
Edit: for any other who reading this and facing the same issue... didnt find any solution for it so switched to react-query. Bye SWR
const { mutate: update } = useSWRConfig();
const updateData = () => {
// this will return promise
update(getURL, updater(putURL, payload)); // update data
mutate(); // refetch data after update
};
By using react-toastify npm module to show the user status.
// first wrap your app with: import { ToastContainer } from "react-toastify";
import { toast } from "react-toastify";
const promise=update(getURL, updater(putURL, payload))
await toast.promise(promise, {
pending: "Mutating data",
success: "muttation is successfull",
error: "Mutation failed",
});
const markSourceMiddleware = (useSWRNext) => (key, fetcher, config) => {
const nextFetcher = (...params) =>
fetcher(...params).then((response) => ({
source: "query",
response,
}));
const swr = useSWRNext(key, nextFetcher, config);
return swr;
};
const useHook = () => {
const {
data: { source, response },
mutate,
} = useSWR(key, fetcher, { use: [markSourceMiddleware] });
const update = mutate(
updateRequest().then((res) => ({
source: "update",
response,
})),
{
optimisticData: {
source: "update",
response,
},
}
);
return {
update,
updating: source === "update",
};
};
Hmm based on that:
https://swr.vercel.app/docs/conditional-fetching
It should work that the "is loading" state is when your updater is evaluates to "falsy" value.
REMAINDER! I don't know react swr just looked into docs - to much time at the end of the weekend :D
At least I hope I'll start discussion :D
I have an App.js file that contains a form that when on submitted, causes triggers a state change to render a new page. I'm trying to create a mock Jest test that does these steps:
Take mock data
Sends a POST request like addInfo is doing
Checks if "DONE WITH FORM" is rendered onto the screen.
I also had an idea that we could just fill out a form that takes in the valid_address and valid_number and click a button that triggers the addInfo function to run with the information passed in however I'm unsure of that method and it leads me to a CORS error.
From what I've seen on the web, I think mocking this addInfo using Jest and then testing what is rendered is the best way to go however I'm completely stuck on building this test.
Here's what I have for my App.js
const addInfo = async (formInfo) => {
try {
let data = {
valid_number: formInfo.validNumber,
valid_address: formInfo.validAddress
}
let addUserUrl = process.env.REACT_APP_URL +'/verify'
let addUserData = await fetch(
addUserUrl,
{
method: "POST",
headers: {
"Content-type": "application/json",
"x-api-key": process.env.REACT_APP_KEY
},
body: JSON.stringify(data)
}
)
if (addUserData.status !== 200) {
throw 'Error adding User'
}
let addUserDataJson = addUserData.json()
let ret = {
added: true,
}
return ret
} catch (error) {
console.log('Error')
let ret = {
added: false,
}
return ret
}
}
const onFinish = async (values: any) => {
console.log('Transaction verified');
let addStatus = await addInfo({
validNumber: "123434",
validAddress: "D74DS8JDSF",
})
if (promoStatus.added) {
setState({
...state,
showPage: false
})
} else {
setState({
...state,
showPage: true
})
}
};
return (
{!state.showPage &&
<>
<div>
<p>
DONE WITH FORM
</p>
<div>
</>
}
)
Here's what I've tried in App.test.js:
it('DONE WITH FORM APPEARS', async() =>{
// Render App
const { getByPlaceholderText, queryByText, getByText } = render(<App />);
// Entering Valid Number
const validNumberInputBox = getByText('Enter Valid Number);
fireEvent.change(validNumberInputBox, { target: { value: "123434" } });
expect(validNumberInputBox).toHaveValue("123434");
// Entering Valid Address
const validAddressInputBox = getByText('Enter Valid Address');
fireEvent.change(validAddressInputBox, { target: { value: "D74DS8JDSF" } });
expect(validAddressInputBox).toHaveValue("D74DS8JDSF");
// Button Click
userEvent.click(screen.getByRole('button', {name: /Submit/i}));
//Check if the DONE WITH FORM is shown
expect(await waitFor(() => getByText('DONE WITH FORM'))).toBeInTheDocument();
});
I've tried almost everything I could find through other stack overflow posts and web articles. so I'd really appreciate any help on how to implement this unit test.
The first step would be to mock the async function performing the POST request (addInfo). You never want to try real HTTP requests in unit tests (this won't work since Jest runs in a Node environment where fetch or XMLHttpRequest APIs are not implemented). Beside this, component/unit tests should be independent from any other system like a backend exposing APIs.
To do so, your async function should be in a separate file (so a JS module), then you could mock this module using Jest :
// api.js
export const addInfo = () => {...}
// App.test.js
import * as Api from 'api.js';
// here you can define what your mock will return for this test suite
const addInfoSpy = jest.spyOn(Api, 'addInfo').mockResolvedValue({ ret: true });
describe('...', () => {
test('...', async () => {
// perform user interactions that should trigger an API call
expect(addInfoSpy).toHaveBeenCalledWith('expected addInfos parameter');
// now you can test that your component displays "DONE WITH FORM" or whatever
// UI it should be displaying after a successful form submission
});
});
https://jestjs.io/docs/mock-function-api#mockfnmockresolvedvaluevalue
https://jestjs.io/docs/jest-object#jestspyonobject-methodname
https://jestjs.io/docs/expect#tohavebeencalledwitharg1-arg2-
So I have a situation where I have this component that shows a user list. First time the component loads it gives a list of all users with some data. After this based on some interaction with the component I get an updated list of users with some extra attributes. The thing is that all subsequent responses only bring back the users that have these extra attributes. So what I need is to save an initial state of users that has a list of all users and on any subsequent changes keep updating/adding to this state without having to replace the whole state with the new one because I don't want to lose the list of users.
So far what I had done was that I set the state in Redux on that first render with a condition:
useEffect(() => {
if(users === undefined) {
setUsers(userDataFromApi)
}
userList = users || usersFromProp
})
The above was working fine as it always saved the users sent the first time in the a prop and always gave priority to it. Now my problem is that I'm want to add attributes to the list of those users in the state but not matter what I do, my component keeps going into an infinite loop and crashing the app. I do know the reason this is happening but not sure how to solve it. Below is what I am trying to achieve that throws me into an infinite loop.
useEffect(() => {
if(users === undefined) {
setUsers(userDataFromApi)
} else {
//Users already exist in state
const mergedUserData = userDataFromApi.map(existingUser => {
const matchedUser = userDataFromApi.find(user => user.name === existingUser.name);
if (matchedUser) {
existingUser.stats = user.stats;
}
return existingUser;
})
setUsers(mergedUserData)
}
}, [users, setUsers, userDataFromApi])
So far I have tried to wrap the code in else block in a separate function of its own and then called it from within useEffect. I have also tried to extract all that logic into a separate function and wrapped with useCallback but still no luck. Just because of all those dependencies I have to add, it keeps going into an infinite loop. One important thing to mention is that I cannot skip any dependency for useCallback or useEffect as the linter shows warnings for that. I need to keep the logs clean.
Also that setUsers is a dispatch prop. I need to keep that main user list in the Redux store.
Can someone please guide me in the right direction.
Thank you!
Since this is based on an interaction could this not be handled by the the event caused by the interaction?
const reducer = (state, action) => {
switch (action.type) {
case "setUsers":
return {
users: action.payload
};
default:
return state;
}
};
const Example = () => {
const dispatch = useDispatch();
const users = useSelector(state => state.users)
useEffect(() => {
const asyncFunc = async () => {
const apiUsers = await getUsersFromApi();
dispatch({ type: "setUsers", payload: apiUsers });
};
// Load user data from the api and store in Redux.
// Only do this on component load.
asyncFunc();
}, [dispatch]);
const onClick = async () => {
// On interaction (this case a click) get updated users.
const userDataToMerge = await getUpdatedUserData();
// merge users and assign to the store.
if (!users) {
dispatch({ type: "setUsers", payload: userDataToMerge });
return;
}
const mergedUserData = users.map(existingUser => {
const matchedUser = action.payload.find(user => user.name === existingUser.name);
if (matchedUser) {
existingUser.stats = user.stats;
}
return existingUser;
});
dispatch({ type: "setUsers", payload: mergedUserData });
}
return (
<div onClick={onClick}>
This is a placeholder
</div>
);
}
OLD ANSWER (useState)
setUsers can also take a callback function which is provided the current state value as it's first parameter: setUsers(currentValue => newValue);
You should be able to use this to avoid putting users in the dependency array of your useEffect.
Example:
useEffect(() => {
setUsers(currentUsers => {
if(currentUsers === undefined) {
return userDataFromApi;
} else {
//Users already exist in state
const mergedUserData = currentUsers.map(existingUser => {
const matchedUser = userDataFromApi.find(user => user.name === existingUser.name);
if (matchedUser) {
existingUser.stats = user.stats;
}
return existingUser;
});
return mergedUserData;
}
});
}, [setUsers, userDataFromApi]);
I took this code from React documentation. But apparently, I am not using it right.
import { useEffect, useRef } from 'react';
export default function usePreviousState(state) {
const ref = useRef();
useEffect(() => {
ref.current = state;
});
return ref.current;
}
This is my functional component:
export default function personInfo({ data, setData }) {
const classes = useStyles();
const prevData = usePreviousState(data);
function handleFieldChange(event) {
setData({
...data,
[event.target.id]: event.target.value,
});
}
async function handleSaveClick(event) {
event.preventDefault();
const formData = normalizeData(data);
try {
if (JSON.stringify(data) !== JSON.stringify(prevData)) {
await updatePeronInfo(formData);
alert('Successfully updated personal information!');
} else {
await createPersonInfo(data);
alert('Your personal information has been saved!');
}
} catch (error) {
handleErrors(error);
}
}
The first problem is, that I cannot post the information, it is always giving me POST and PATCH, but it is throwing 404 error Page not found, so it did not create or update the information at all. If I change the if statement from (JSON.stringify(data) !== JSON.stringify(prevData)) to (JSON.stringify(data) === JSON.stringify(prevData)) somehow it manage to POST the data. But later on if I want to update the info it appears that it is trying to execute createPersonInfo, which leads to an error 500 Internal Server Error because it is already created. Any idea what I am doing wrong, and what I am missing in the "IF LOGIC". Apparently, prevData is undefined at the beginning. How should I fix that?
You need to add simple check:
if (typeof prevData !== 'undefined') {
if (JSON.stringify(data) !== JSON.stringify(prevData)) {...}
} else {...}
I am trying to load a notification token (notificationToken) that I've stored within Firebase to a React Native component.
Once the notificationToken is loaded to my redux state, I want to check for my device permissions to see if the notificationToken has expired within the function getExistingPermission() that I run in the componentDidMount().
If the token has expired, then I'll replace the token within Firebase with the new token. If it's the same, then nothing happens (which is intended functionality).
When I'm running my function getExistingPermission() to check if the token is up-to-date the Firebase listener that pulls the notificationToken does not load in time, and so it's always doing a write to the Firebase database with a 'new' token.
I'm pretty sure using async/await would solve for this, but have not been able to get it to work. Any idea how I can ensure that the notificationToken loads from firebase to my redux state first before I run any functions within my componentDidMount() function? Code below - thank you!
src/screens/Dashboard.js
Should I use a .then() or async/await operator to ensure the notificationToken loads prior to running it through the getExistingPermission() function?
import {
getExistingPermission
} from '../components/Notifications/NotificationFunctions';
componentDidMount = async () => {
// Listener that loads the user, reminders, contacts, and notification data
this.unsubscribeCurrentUserListener = currentUserListener((snapshot) => {
try {
this.props.watchUserData();
} catch (e) {
this.setState({ error: e, });
}
});
if (
!getExistingPermission(
this.props.notificationToken, //this doesn't load in time
this.props.user.uid)
) {
this.setState({ showNotificationsModal: true });
}
};
src/components/Notifications/NotificationFunctions.js
The problem is probably not here
export const getExistingPermission = async (
notificationToken,
uid,
) => {
const { status: existingStatus } = await Permissions.askAsync(
Permissions.NOTIFICATIONS
);
if (existingStatus !== 'granted') {
console.log('status not granted');
return false;
} else {
let token = await Notifications.getExpoPushTokenAsync();
/* compare to the firebase token; if it's the same, do nothing,
if it's different, replace */
if (token === notificationToken) {
console.log('existing token loaded');
return true;
} else {
console.log('token: ' + token);
console.log('notificationToken: ' + notificationToken);
console.log('token is not loading, re-writing token to firebase');
writeNotificationToken(uid, token);
return false;
}
}
};
src/actions/actions.js
// Permissions stuff
watchPermissions = (uid) => (
(dispatch) => {
getPermissions(uid + '/notificationToken', (snapshot) => {
try {
dispatch(loadNotificationToken(Object.values([snapshot.val()])[0]));
}
catch (error) {
dispatch(loadNotificationToken(''));
// I could call a modal here so this can be raised at any point of the flow
}
});
}
);
// User Stuff
export const watchUserData = () => (
(dispatch) => {
currentUserListener((user) => {
if (user !== null) {
console.log('from action creator: ' + user.displayName);
dispatch(loadUser(user));
dispatch(watchReminderData(user.uid)); //listener to pull reminder data
dispatch(watchContactData(user.uid)); //listener to pull contact data
dispatch(watchPermissions(user.uid)); //listener to pull notificationToken
} else {
console.log('from action creator: ' + user);
dispatch(removeUser(user));
dispatch(logOutUser(false));
dispatch(NavigationActions.navigate({ routeName: 'Login' }));
}
});
}
);
export const loadNotificationToken = (notificationToken) => (
{
type: 'LOAD_NOTIFICATION_TOKEN',
notificationToken,
}
);
Tony gave me the answer. Needed to move the permissions check to componentDidUpdate(). For those having a similar issue, the component looks like this:
src/screens/Dashboard.js
componentDidUpdate = (prevProps) => {
if (!prevProps.notificationToken && this.props.notificationToken) {
if (!getExistingPermission(
this.props.notificationToken,
this.props.user.uid
)) {
this.setState({ showNotificationsModal: true });
}
}
};
Take a look at redux subscribers for this: https://redux.js.org/api-reference/store#subscribe . I implement a subscriber to manage a small state machine like STATE1_DO_THIS, STATE2_THEN_DO_THAT and store that state in redux and use it to render your component. Only the subscriber should change those states. That gives you a nice way to handle tricky flows where you want to wait on action1 finishing before doing action2. Does this help?