Develop Reference

State is undefined, but ONLY in Test Flight

I have the following component with the following functions (alerts included to show where state is weird):
const CategoryArticlesChild = (props) => {
const categories = useSelector((state) => state.settings.cats);
const show_read = useSelector((state) => state.settings.show_read);
const skills = useSelector((state) => state.settings.skill);
const date = useSelector((state) => state.date);
...
const loadArticlesByCategory = () => {
const hsks = getLevels(skills);
const limit = (categories.length + 1) * 15;
let _query = {
category: categories,
limit: limit,
ordering: "-date",
published: 1,
display_skill: hsks,
taxon: props.taxon,
show_read: show_read,
};
alert(JSON.stringify(_query));
alert(JSON.stringify(date));
_query = processDates(date, _query);
if (!_.isEqual(query, _query)) {
setQuery(_query);
} else {
setIsLoading(false);
}
};
useEffect(() => {
if (!isLoading) {
setIsLoading(true);
}
if (
categories &&
skills &&
!_.isUndefined(date) &&
date &&
show_read !== null
) {
loadAllArticles();
}
}, [categories, date, skills, show_read]);
...
}
The ONLY place that loadArticlesByCategory is called is in the useEffect above.
And on web (I am using React Native Web), iOS simulator and Xcode build on device, it all works fine.
But then when I push to Test Flight, date is undefined. Even though, as you can see, I use a Lodash function to check DIRECTLY if it is undefined, and prevent execution of the function if it isn't defined.
What exactly am I missing here? Why is date constantly undefined, but ONLY in Test Flight, and despite me setting code that should explicitly stop it from being undefined

Changing the code to the following (and also added the arguments to the other function):
useEffect(() => {
if (!isLoading) {
setIsLoading(true);
}
if (
categories &&
skills &&
!_.isUndefined(date) &&
date &&
show_read !== null
) {
loadArticlesByCategory(categories, skills, date, show_read);
}
}, [categories, date, skills, show_read]);
Fixed this particular bug.
So my best guess is that this is some sort of React immutability issue or some sort of race condition?

ToDo complete status not staying saved in storage in React Native

Edit - added minimally reproducible example: https://snack.expo.dev/#hdorra/code
I hope everyone can access the snack. So if you add a task, you can see it show up in the log. Click on the circle, it shows as true (meaning it is clicked). Save and refresh and everything is stored (the task) but the checkbox is not. I stripped the code to make it as bare minimum as possible but it shows the problem.
It has been days of me on this error. I am relatively new to stackoverflow so my apologies if my question isn't clear or I am not asking it in the correct format. I am trying to create a to do app in react native that is using async storage. I created a toggle button that saves the toggle to a state. This button is located in a component:
const [checkBoxState, setCheckBoxState] = React.useState(false);
const toggleComplete = () => {
setCheckBoxState(!checkBoxState)
handleEdit();
console.log(checkBoxState)
}
When the user checks on it - seems to be showing up correctly as marked true and false in the console.
Then, this is passed to an edit handler to update the array, again console shows it is the correct state:
const handleEdit = () => {
props.editHandler(props.todoKey, text, checkBoxState);
console.log(text2, checkBoxState)
};
Then it shows that it saved correctly:
const [todos, setTodos] = React.useState([]);
const handleEdit = (todoKey, text, newStatus) => {
const newTodos = [...todos];
const index = newTodos.findIndex(todos => todos.key === todoKey);
newTodos[index] = Object.assign(newTodos[index], {title: text, status: newStatus});
setTodos(newTodos);
console.log(todos, newStatus)
};
The async function to save to the device and load are as follows:
To save:
const saveTodoToUserDevice = async (todos) => {
try {
const stringifyTodos = JSON.stringify(todos);
await AsyncStorage.setItem('todos', stringifyTodos);
} catch (error) {
console.log(error);
}
};
To load from the device:
const getTodosFromUserDevice = async () => {
try {
const todos = await AsyncStorage.getItem('todos');
if (todos != null) {
setTodos(JSON.parse(todos));
console.log("loaded successfully");
}
} catch (error) {
console.log(error);
}
};
So here is the issue - I get the console log that says it is saved correctly and loaded. BUT, when I refresh, the checkbox state is not saved at all, just the title text (so it is saving but the checkbox would always be false (the initial state set). If I clicked on true, it would show as true and then when I refresh, it goes back to false.
I have spent days and days on this and can't figure it out. Any direction would be helpful Thank you!

I have gone through your code and found some errors you are making in different places. In Task.js you can do without that checkBoxState. For that, pass the status to Task as props while rendering it in FlatList, like so:
<Task
key={item.key}
todoKey={item.key}
title={item.title}
status={item.status}
editHandler={handleEdit}
pressHandler={handleDelete}
/>
Then as below, change the button to toggle the status, so you use what's coming from the props and create a function called toggleStatus and pass it to onPress:
<TouchableOpacity onPress={toggleStatus}>
<View
style={[
styles.circle,
!props.status ? styles.completeCircle : styles.incompleteCircle,
]}
></View>
</TouchableOpacity>
The code for toggleStatus:
const toggleStatus = () => {
props.editHandler(props.todoKey, props.title, !props.status);
};
And handleEdit would be simplified to:
const handleEdit = () => {
props.editHandler(props.todoKey, text2, props.status);
setEdit(false);
console.log(props.status);
};
Lastly, in TasksMain.js so you don't replace what's in the storage with that initial array given to useState, make sure saveTodoToUserDevice runs after getTodosFromUserDevice. For that, add the below state in TasksMain.js and slightly change the two functions as follow:
const [loading, setLoading] = React.useState(true);
const saveTodoToUserDevice = async (todos) => {
if (loading) return;
try {
const stringifyTodos = JSON.stringify(todos);
await AsyncStorage.setItem("todos", stringifyTodos);
} catch (error) {
console.log(error);
}
};
const getTodosFromUserDevice = async () => {
try {
const todos = await AsyncStorage.getItem("todos");
if (todos != null) {
setTodos(JSON.parse(todos));
console.log("loaded successfully");
}
} catch (error) {
console.log(error);
} finally {
setLoading(false);
}
};

How to put a dynamic data from firestore in the function where() and also use the snap.size to count the total query to be passed in a graph?

I have this data from firestore and I wanted to retrieve it dynamically with a where() but this is the error I'm getting:
TypeError: vaccines is not a function
The user collection:
[![enter image description here][1]][1]
Below are the codes:
const Vaccine = () => {
const [vaccines, setVaccines] = useState([]);
useEffect(() => {
const unsubscribe = firestore
.collection("vaccines")
.onSnapshot((snapshot) => {
const arr = [];
snapshot.forEach((doc) =>
arr.push({
...doc.data(),
id: doc.id,
})
);
setVaccines(arr);
});
return () => {
unsubscribe();
};
}, []);

Preface
As highlighted in the comments on the original question, this query structure is not advised as it requires read access to sensitive user data under /users that includes private medical data.
DO NOT USE THIS CODE IN A PRODUCTION/COMMERICAL ENVIRONMENT. Failure to heed this warning will lead to someone suing you for breaches of privacy regulations.
It is only suitable for a school project (although I would a fail a student for such a security hole) or proof of concept using mocked data. The code included below is provided for education purposes, to solve your specific query and to show strategies of handling dynamic queries in React.
From a performance standpoint, in the worst case scenario (a cache miss), you will be billed one read, for every user with at least one dose of any vaccine, on every refresh, for every viewing user. Even though your code doesn't use the contents of any user document, your code must download all of this data too because the Client SDKs do not support the select() operator.
For better security and performance, perform this logic server-side (e.g. Cloud Function, a script on your own computer, etc) and save the results to a single document that can be reused by all users. This will allow you to properly tighten access to /users. It also significantly simplifies the code you need to display the graphs and live statistics on the client-side.
useEffect
As stated by the React documentation on the Rules of hooks:
Only Call Hooks at the Top Level
Don’t call Hooks inside loops, conditions, or nested functions. Instead, always use Hooks at the top level of your React function, before any early returns. By following this rule, you ensure that Hooks are called in the same order each time a component renders. That’s what allows React to correctly preserve the state of Hooks between multiple useState and useEffect calls.
The documentation further elaborates that React relies on the order in which Hooks are called, which means that you can't have hook definitions behind conditional logic where their order and quantity changes between renders. If your hooks rely on some conditional logic, it must be defined inside of the hook's declaration.
As an example, if you have an effect that relies on other data, with this logic:
const [userProfile, setUserProfile] = useState();
const [userPosts, setUserPosts] = useState(null);
useEffect(() => {
// get user profile data and store in userProfile
}, []);
if (userProfile) {
useEffect(() => {
// get user post list and store in userPosts
}, [userProfile]);
}
you need to instead use:
const [userProfile, setUserProfile] = useState();
const [userPosts, setUserPosts] = useState(null);
useEffect(() => {
// get user profile data and store in userProfile
}, []);
useEffect(() => {
if (!userProfile) {
// not ready yet/signed out
setUserPosts(null);
return;
}
// get user post list and store in userPosts
}, [userProfile]);
Similarly, for arrays:
someArray && someArray.forEach((entry) => {
useEffect(() => {
// do something with entry to define the effect
}, /* variable change hooks */);
});
should instead be:
useEffect(() => {
if (!someArray) {
// not ready yet
return;
}
const cleanupFunctions = [];
someArray.forEach((entry) => {
// do something with entry to define an effect
cleanupFunctions.push(() => {
// clean up the effect
});
});
// return function to cleanup the effects created here
return () => {
cleanupFunctions.forEach(cleanup => cleanup());
}
}, /* variable change hooks */);
Because this looks a lot like lifecycle management, you are actually better off replacing it with nested components rather than using hooks, like so:
return (
<> // tip: React.Fragment shorthand (used for multiple top-level elements)
{
someArray && someArray
.map(entry => {
return <Entry key={entry.key} data={entry.data} />
})
}
</>
);
Adapting to your code
Note: The code here doesn't use onSnapshot for the statistics because it would cause a rerender every time a new user is added to the database.
const getVaccineStats = (vaccineName) => {
const baseQuery = firestore
.collection("users")
.where("doses.selectedVaccine", "==", vaccine);
const oneDoseQueryPromise = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", false)
.get()
.then(querySnapshot => querySnapshot.size);
const twoDoseQueryPromise = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", true)
.get()
.then(querySnapshot => querySnapshot.size);
return Promise.all([oneDoseQueryPromise, twoDoseQueryPromise])
.then(([oneDoseCount, twoDoseCount]) => ({ // tip: used "destructuring syntax" instead of `results[0]` and `results[1]`
withOneDose: oneDoseCount,
withTwoDoses: twoDoseCount
}));
};
const Vaccine = () => {
const [vaccines, setVaccines] = useState();
const [vaccineStatsArr, setVaccineStatsArr] = useState([]);
// Purpose: Collect vaccine definitions and store in `vaccines`
useEffect(() => {
return firestore // tip: you can return the unsubscribe function from `onSnapshot` directly
.collection("vaccines")
.onSnapshot({ // tip: using the Observer-like syntax, allows you to handle errors
next: (querySnapshot) => {
const vaccineData = []; // tip: renamed `arr` to indicate what the data contains
querySnapshot.forEach((doc) =>
vaccineData.push({
...doc.data(),
id: doc.id,
});
);
setVaccines(vaccineData);
}),
error: (err) => {
// TODO: Handle database errors (e.g. no permission, no connection)
}
});
}, []);
// Purpose: For each vaccine definition, fetch relevant statistics
// and store in `vaccineStatsArr`
useEffect(() => {
if (!vaccines || vaccines.length === 0) {
return; // no definitions ready, exit early
}
const getVaccineStatsPromises = vaccines
.map(({ vaccine }) => [vaccine, getVaccineStats(vaccine)]);
// tip: used "destructuring syntax" on above line
// (same as `.map(vaccineInfo => [vaccineInfo.vaccine, getVaccineStats(vaccineInfo.vaccine)]);`)
let unsubscribed = false;
Promise.all(getVaccineStatsPromises)
.then(newVaccineStatsArr => {
if (unsubscribed) return; // unsubscribed? do nothing
setVaccineStatsArr(newVaccineStatsArr);
})
.catch(err => {
if (unsubscribed) return; // unsubscribed? do nothing
// TODO: handle errors
});
return () => unsubscribed = true;
}, [vaccines]);
if (!vaccines) // not ready? hide element
return null;
if (vaccines.length === 0) // no vaccines found? show error
return (<span class="error">No vaccines found in database</span>);
if (vaccineStatsArr.length === 0) // no stats yet? show loading message
return (<span>Loading statistics...</span>);
return (<> // tip: React.Fragment shorthand
{
vaccineStatsArr.map(([name, stats]) => {
// this is an example component, find something suitable
// the `key` property is required
return (<BarGraph
key={name}
title={`${name} Statistics`}
columns={["One Dose", "Two Doses"]}
data={[stats.withOneDose, stats.withTwoDoses]}
/>);
});
}
</>);
};
export default Vaccine;
Live Statistics
If you want your graphs to be updated live, you need "zip together" the two snapshot listeners into one, similar to the rxjs combineLatest operator. Here is an example implementation of this:
const onVaccineStatsSnapshot => (vaccine, observerOrSnapshotCallback, errorCallback = undefined) => {
const observer = typeof observerOrCallback === 'function'
? { next: observerOrSnapshotCallback, error: errorCallback }
: observerOrSnapshotCallback;
let latestWithOneDose,
latestWithTwoDoses,
oneDoseReady = false,
twoDosesReady = false;
const fireNext = () => {
// don't actually fire event until both counts have come in
if (oneDoseReady && twoDosesReady) {
observer.next({
withOneDose: latestWithOneDose,
withTwoDoses: latestWithTwoDoses
});
}
};
const fireError = observer.error || (err) => console.error(err);
const oneDoseUnsubscribe = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", false)
.onSnapshot({
next: (querySnapshot) => {
latestWithOneDose = querySnapshot.size;
oneDoseReady = true;
fireNext();
},
error: fireError
});
const twoDoseUnsubscribe = baseQuery
.where("doses.dose1", "==", true)
.where("doses.dose2", "==", true)
.onSnapshot({
next: (querySnapshot) => {
latestWithTwoDoses = querySnapshot.size;
twoDosesReady = true;
fireNext();
},
error: fireError
});
return () => {
oneDoseUnsubscribe();
twoDoseUnsubscribe();
};
}
You could rewrite the above function to make use of useState, but this would unnecessarily cause components to rerender when they don't need to.
Usage (direct):
const unsubscribe = onVaccineStatsSnapshot(vaccineName, {
next: (statsSnapshot) => {
// do something with { withOneDose, withTwoDoses } object
},
error: (err) => {
// TODO: error handling
}
);
or
const unsubscribe = onVaccineStatsSnapshot(vaccineName, (statsSnapshot) => {
// do something with { withOneDose, withTwoDoses } object
});
Usage (as a component):
const VaccineStatsGraph = (vaccineName) => {
const [stats, setStats] = useState(null);
useEffect(() => onVaccineStatsSnapshot(vaccineName, {
next: (newStats) => setStats(newStats),
error: (err) => {
// TODO: Handle errors
}
}, [vaccineName]);
if (!stats)
return (<span>Loading graph for {vaccineName}...</span>);
return (
<BarGraph
title={`${name} Statistics`}
columns={["One Dose", "Two Doses"]}
data={[stats.withOneDose, stats.withTwoDoses]}
/>
);
}

vaccines is an array and not a function. You are trying to run a map on vaccines. Try refactoring your code to this:
vaccines &&
vaccines.map((v, index) => {
// ...
})
Also do check: How to call an async function inside a UseEffect() in React?

here is the code, that works for you:
function DatafromFB() {
const[users, setUsers] = useState({});
useEffect(()=>{
const fetchVaccine = async () => {
try {
const docs = await db.collection("vaccines").get();;
docs.forEach((doc) => {
doc.data().vaccineDetails
.forEach(vaccineData=>{
fetchUsers(vaccineData.vaccine)
})
})
} catch (error) {
console.log("error", error);
}
}
const fetchUsers = async (vaccine)=>{
try {
const docs = await db.collection("users")
.where("doses.selectedVaccine", "==", vaccine).get();
docs.forEach(doc=>{
console.log(doc.data())
setUsers(doc.data());
})
}catch(error){
console.log("error", error);
}
}
fetchVaccine();
},[])
return (
<div>
<h1>{users?.doses?.selectedVaccine}</h1>
</div>
)
}
export default DatafromFB

what is ${index.vaccine} I think it must be v.vaccine
also setSize(snap.size); will set set size commonly not vaccine specific

Really need some help figuring out the logic of componentWillMount() prior to render

this might be kind of long read, I've read and tried so many solutions without success! Essentially what I have is three MySQL tables, one with a list of users, and one with a list of file data. They are paired with a third table, which has a column for user id and a column for file id.
When a user logs into the app, it grabs their ID from Table 1, goes to Table 3, finds all the file IDs that are in the same row as their user ID, and then returns the file information from Table 2. Mostly straight forward, except it's not.
My current code:
componentWillMount() {
this.getClientFiles();
}
Which calls:
getClientFiles() {
let id = this.props.currentUser.user_id;
let file_refs = [];
axios.get(`/users/get-client-files/${id}`)
.then(res => {
let response = res.data.response;
for (let i = 0; i < response.length; i++) {
file_refs.push(response[i].file_id);
}
this.setState({
file_refs
});
this.getFileData();
});
}
My understanding of this is that this.getFileData(); should ONLY run once the axios GET request is successful (because of .then). The file refs are all returned, and the added to an array and put in state for the duration of the client's session.
Then this should run:
getFileData() {
let fileRefs = this.state.file_refs;
let fileData = [];
for (let i = 0; i < fileRefs.length; i++) {
axios
.get("/files/get-file/" + fileRefs[i])
.then(res => {
fileData.push(res.data.response);
this.setState({
client_files: fileData,
returned_data: true
});
})
.catch(err => console.log(err.response.data));
}
}
Here, the function cycles through the fileRefs in state, makes a call for each reference ID, and returns that to fileData and saves it to state.
The problem.... on first page load after a login, the files do not render. If you hit cmd+R to refresh, boom there they are. I understand the chain of promises, and the async nature of JS functions, I understand that componentWillMount() should run prior to the mounting of the component, and that setState should trigger a re-render of a component.
Things I've tried:
1) Adding the following code in after render() prior to return( :
if (this.state.returned_data === false) {
this.getClientFiles();
}
The result is a flickering of renders, 4-5 of them, as the functions run async before the state of returned_data is set to true.
2) Moving the setState({ returned_data: true }) into the getClientFiles() function. This just ends the render early, resulting in no files until the page is refreshed.
3) Swapping out componentWillMount() for componentDidMount().
Clearly, there is a fundamental aspect of the chain of functions and React's built in methods that I'm missing.
Can anybody help?
EDIT #1
The issue seems to be that on first render, let id = this.props.currentUser.user_id; is undefined, so the call in getClientFiles is actually going to /users/get-client-files/undefined
EDIT #2 - Requested by #devserkan
I hope this is what you wanted :)
First load
get-client-files/${id}: Returns an empty array
/get-file/" + fileRefs[i]: Doesn't run
Second load:
get-client-files/${id}: Returns array with 5 items
/get-file/" + fileRefs[i]: Runs appropriately 5 times with the details of each file.
So clearly, the issue is with the fact that get-client-files/${id} isn't getting anything because it doesn't have the ${id} to search from. The ID is passed down via props, but doesn't seem to be available immediately.
EDIT #3
Here is the function that gets the ID, and sets it to state.
getUser = () => {
let localToken = localStorage.getItem("iod_tkn");
axios({
url: "/admins/current",
method: "get",
headers: {
Authorization: localToken
}
})
.then(result => {
this.setState({
isLoggedIn: true,
user: result.data,
user_id: result.data.user_id
});
})
.catch(err => {
this.setState({ isLoggedIn: false });
console.log(err);
});
};
And App.js renders the following:
render() {
const { loading } = this.state;
if (loading) {
return <Spinner />;
}
return (
<AdminProvider>
<FileProvider>
<Provider>
<Appbar isLoggedIn={this.state.isLoggedIn} logout={this.logout} />
<Main
getUser={this.getUser}
isLoggedIn={this.state.isLoggedIn}
currentUser={this.state.user}
/>
<BottomNav />
</Provider>
</FileProvider>
</AdminProvider>
);
}
So with passing this.state.user into Main.js, that component should re-render once the props have been received, right?

Since your user_id is coming from an async job, you should do a conditional rendering. Like:
{ user_id && <ClientDashboard user_id={user_id} ... /> }
Also, you can clean up your code a little bit more maybe :) Here I am mimicking your app.
const userFiles = [
{ file_id: 1, client_name: "foo" },
{ file_id: 2, client_name: "bar" },
{ file_id: 3, client_name: "baz" },
];
const files = [
{ file_id: 1, name: "fizz", size: 10 },
{ file_id: 2, name: "buzz", size: 20 },
{ file_id: 3, name: "fuzz", size: 30 },
];
const fakeRequest = () => new Promise( resolve =>
setTimeout( () => resolve(userFiles), 1000)
);
const fakeRequest2 = id => new Promise(resolve => {
const file = files.find( el => id === el.file_id );
setTimeout(() => resolve(file), 1000)
}
);
class App extends React.Component {
state = {
file_refs: [],
client_files: [],
returned_data: false,
}
componentDidMount() {
this.getClientFiles();
}
getClientFiles() {
fakeRequest()
.then(res => {
const file_refs = res.map( el => el.file_id );
this.setState({
file_refs
});
this.getFileData();
});
}
getFileData() {
const {file_refs: fileRefs} = this.state;
const promiseArray = fileRefs.map( id => fakeRequest2( id ) );
Promise.all( promiseArray )
.then( results => this.setState({
client_files: results,
returned_data: true,
}))
}
render() {
const { file_refs, client_files } = this.state;
return (
<div>
{!!file_refs.length && <p>File_refs: {JSON.stringify(file_refs)}</p>}
{!!client_files.length && <p>Client files: {JSON.stringify(client_files)}</p>}
</div>
);
}
}
ReactDOM.render(<App />, document.getElementById("root"));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>
I don't like for loops :)

The problem is that in componentWillMount() an async call might not retrieve the results on time before the render of the mount phase happens, so you will have unexpected side effects. Most probably the component will render with empty data.
The best place to render data from an async call is componentDidMount().
As a side note, from 16.3 version on, componentWillMount() is considered an unsafe method of the lifecycle, and in future versions will be removed, so you better not use it anymore.

I think there's an issue with your code structuring. setState is an async function which takes a callback as a second parameter. You should take its advantage. You can execute a function after setState is finishing and utilize updated state using the second param callback (updater function) like:
this.setState({
file_refs
}, () => {
this.getFileData();
});
EDITED Second option you shouldn't setState file_refs unless you're using it in your render method.
Try this:
axios.get(`/users/get-client-files/${id}`)
.then(res => {
let response = res.data.response;
for (let i = 0; i < response.length; i++) {
file_refs.push(response[i].file_id);
}
this.getFileData(file_refs);
});
getFileData(file_refs) {
let fileRefs = file_refs;
let fileData = [];
// rest of your code
}
Let me know if the issue still persists. Happy to help

Node and React are not in sync

I was able to achieve the following -> When a user clicks on a particular date in component A the data gets sent to the Node (Sails API) where all the necessary calculations are done, and before component B is rendered the correct data is ready to be shown.
The problem is when a user returns back from component B to component A and chooses a different date, he/ she gets the exact same result (old value) because even though the new value is sent to the backend API, Node isn't doing the recalculations with the new value.
I'm only able to achieve the correct result after I manually refresh the page, or make changes to the server so it forces the recalculation.
I think I need to mention that I'm passing data using Redux, so maybe the issue occurs on that part.
I would consider some type of auto refresh, animated loading, anything.
Yup, so stuck :/
Is it even possible to make them in total sync?
UPDATE --> Here is the code:
BACKEND
getDetails: (req, res) => {
authentication.authenticate().then((auth) => {
const sheets = google.sheets('v4');
sheets.spreadsheets.values.get({
auth: auth,
spreadsheetId: config.spreadsheetSettings.spreadsheetId, // id of spreadsheet
range: config.spreadsheetSettings.employeeSheetId, // name of employee spreadsheet and range- get all cells
}, (err, response) => {
if (err) {
res.serverError(err);
return;
}
const rows = response.values; // response-all cells
const updatedData = employeeService.mapEmployeeSheetToJson(rows);
// FETCHING THE VALUE FROM REST API
let myArr = [];
(function() {
axios.get(`http://localhost:1337/api/`)
.then(res => {
let kajmak = res.data.slice(-1)[0]
let test = kajmak[Object.keys(kajmak)[0]]
myArr.push(test)
}).catch(err => console.error(err));
})();
// MAPING OVER THE ARRY AND DOING THE LOGIC
setTimeout(() => {
myArr.map(xo => {
const result = [];
updatedData.forEach(emp => {// 2013 2012 2014
if (xo > parseInt(moment(emp.startdate).format('YYYYMM'), 10) &&
(xo < parseInt(moment(emp.enddate).format('YYYYMM'), 10))) {
result.push(emp);
}
});
// IF THEY STARTED WORKING BEFORE THE SELECTED DATE AND STILL WORKING
updatedData.forEach(emp => { // 2013 > 2012 & 2013 -
if (xo > parseInt(moment(emp.startdate).format('YYYYMM'), 10) &&
((parseInt(moment(emp.enddate).format('YYYYMM'), 10) == undefined ))) {
result.push(emp);
}
});
// IF THEY STARTED WORKIG BEFORE THE SELECTED DATE,
// BUT STOPPED WORKING BEFORE THE SELECTED DATE
updatedData.forEach(emp => { // 2013 < 2014 || 2013 > 2017
if (xo < parseInt(moment(emp.startdate).format('YYYYMM'), 10) &&
(xo > parseInt(moment(emp.startdate).format('YYYYMM'), 10))) {
result.pop(emp);
}
});
// Getting the names to use for unique sheet req
let finalResult = [];
result.map(x => {
finalResult.push((x.name + ' ' + x.surname))
})
if (rows.length === 0) {
res.err('No data found.');
} else {
res.ok(finalResult);
}
})
}, 1000);
});
}
FRONTEND
getEmployeeSalaryData = () => {
// GETTING THE CLICKED VALUE FROM THE PREVIOUS COMPONENT
const { year } = this.props.history.location.state.item;
const { month } = this.props.history.location.state.item;
const selectedMonth = moment().month(month).format("MM");
const finalSelect = parseInt(year + selectedMonth, 10);
const { employees } = this.props;
// I'M RECIEVING THIS AS PROPS USING REDUX AND THIS IS THE ACTUAL 'FINAL' DATA USED FOR FURTHER CALCS AND RENDERING
const { details } = this.props;
// HERE I'M SENDING THE 'CLICKED' VALUE FROM THE PREVIOUS COMPONENT TO THE BACKEND API
axios.post(`http://localhost:1337/api/`, { 'test' : finalSelect })
.then(res => {
console.log('Data send')
// console.log(res.data);
}).catch(err => console.error(err));
// Making the req
details.map(x => {
EmployeeApi.getEmployee(x)
.then(y => {
//Making sure everything is in the right order
let test = Object.assign(y.data);
let ii = x;
setTimeout(
this.setState(prevState => ({
...prevState.currentEmployee,
fullNames: [...prevState.currentEmployee.fullNames, ii]
})), 100);
let onlyRelevantDate = [];
test.map(item => {
if (finalSelect == parseInt(item.year + moment().month(item.month).format("MM"), 10)) {
onlyRelevantDate.push(item)
}})
this.setState(prevState => ({
currentEmployee: {
...prevState.currentEmployee,
salaryInfo: [...prevState.currentEmployee.salaryInfo, onlyRelevantDate],
fullNames: [...prevState.currentEmployee.fullNames, ii]
}}))
})
});
}
componentWillReceiveProps(nextProps) {
this.getEmployeeSalaryData(nextProps);
}
componentWillMount() {
this.getEmployeeSalaryData(this.props);
}

In component A you should dispatch an action that is a function taking a dispatch function.
//some click handler for when user makes a selection
// the function should be in action creator file but you get the jist
const handleSomeClick = someValue =>
//when you dispatch an action that is a function in redux with thunk then
// the thunk middleware will not call next (no reducers will be called)
// thunk will pass a parameter to this function that is the dispatch
// function so from your function you can dispatch actual object action(s)
dispatch(
dispatch=>
setTimeout(
dispatch({type:"changedValue",data:someValue}),//dispatching the action
someValue*1000//assuming someValue is a number
)
)
Here is an example that has component A set someValue depending on what button is clicked and will highlight that button it'll also set someValue of B asynchronously. This is done in the function changeLater that dispatches an action that is a function so thunk will execute it with the dispatch.
This function will dispatch an action after a timeout. If you click the numbers 5 and then 1 (quickly) you'll see that the highlighted button of A and value after async of B do not match (highlighted of A is 1 and value after async of B is showing 5).
This is because the order of which the user clicks and starts the async process is not the same as the order the async process resolves. You could solve this by only dispatching an action when it's the last resolved promise.
This example shows how it's done by using a promise created by later and only resolve it if it's the last by using a partially applied version of onlyLastRequestedPromise called lastNumberClicked

you can use RxJS to solve this