Develop Reference

getServerSideProps not fetching data despite of running it inside the page

hello i am trying to fetch data inside by next app using getServerSideProps which is just not fetching the data , the data returns either an empty object or undefined inside the console i don't know what is wrong with the app , i have tried other next js data-fetching methods too and results are same
export const getServerSideProps = async () => {
// Fetch data from external API
const res = await fetch(`https://rickandmortyapi.com/api/character`)
const data = await res.json()
console.log(data)
// Pass data to the page via props
return { props: { data } }
}

I threw that code into my current project and it works.
interface Props {
data: {
info: any;
results: any[];
}
}
const Page: NextPage<Props> = ({ data }) => {
console.log(data); // { info: {...}, results: Array(20)}
// ...
}
export const getServerSideProps = async () => {
const res = await fetch('https://rickandmortyapi.com/api/character');
const data = await res.json();
return { props: { data } };
};

React Prop returning Null as it relies on state

Hopefully a simply one.
I make an API call in my component which brings down some account information such as AccountUid, Category etc, i use state to set these.
useEffect(() => {
fetch(feed_url, {
headers: {
//Headers for avoiding CORS Error and Auth Token in a secure payload
"Access-Control-Allow-Origin": "*",
Authorization: process.env.REACT_APP_AUTH_TOKEN,
},
})
//Return JSON if the Response is recieved
.then((response) => {
if (response.ok) {
return response.json();
}
throw response;
})
//Set the Account Name state to the JSON data recieved
.then((accountDetails) => {
setAccountDetails(accountDetails);
console.log(accountDetails.accounts[0].accountUid);
console.log(accountDetails.accounts[0].defaultCategory);
})
//Log and Error Message if there is an issue in the Request
.catch((error) => {
console.error("Error fetching Transaction data: ", error);
});
}, [feed_url]);
This Works perfectly well and it Logs the correct values in my .then when testing it.
The issue however is that i want to pass these down as props. But i get an error that they are being returned as null (My default state).. i presume as they're jumping ahead.
<div className="App">
<GetAccountName
accountUID={accountDetails.accounts[0].accountUID}
defCategory={accountDetails.accounts[0].defaultCategory}
/>
</div>
How do i pass the the 2 details im logging as props?? I've tried setting default state to "" instead of null and just get that it is undefined.

If you dont want to use conditional render in your child component, so you should try optional chaining
<GetAccountName
accountUID={accountDetails?.accounts?.[0]?.accountUID}
defCategory={accountDetails?.accounts?.[0]?.defaultCategory}
/>

Since fetching is asyncronous, the most common way is to show some loading indicator (like a spinner) & once the data come in, show the component instead.
If you don't need an indicator, you might just return null.
The general idea is to manipulate some intermediary states (e.g. data, isError) based on the promise state.
Check out react-query library example or a lighter abstraction like useFetch hook to see how they manage it.
Here's a sample implementation of useFetch taken from this article:
const useFetch = (url, options) => {
const [response, setResponse] = React.useState(null);
const [error, setError] = React.useState(null);
const [abort, setAbort] = React.useState(() => {});
React.useEffect(() => {
const fetchData = async () => {
try {
const abortController = new AbortController();
const signal = abortController.signal;
setAbort(abortController.abort);
const res = await fetch(url, {...options, signal});
const json = await res.json();
setResponse(json);
} catch (error) {
setError(error);
}
};
fetchData();
return () => {
abort();
}
}, []);
return { response, error, abort };
};

Data Not updated when fetch query - React-Query?

I have a three-check box type,
When I check any box I call refetch() in useEffect().
The first time, I check all boxes and that returns the expected data!
but for some cases "rechange the checkboxes randomly", the returned data from API is "undefined" although it returns the expected data in Postman!
So I Guess should I need to provide a unique queryKey for every data that I want to fetch
so I provide a random value "Date.now()" but still return undefined
Code snippet
type bodyQuery = {
product_id: number;
values: {};
};
const [fetch, setFetch] = useState<number>();
const [bodyQuery, setBodyQuery] = useState<bodyQuery>({
product_id: item.id,
values: {},
});
const {
data: updatedPrice,
status,
isFetching: loadingPrice,
refetch,
} = useQuery(
['getUpdatedPrice', fetch, bodyQuery],
() => getOptionsPrice(bodyQuery),
{
enabled: false,
},
);
console.log('#bodyQuery: ', bodyQuery);
console.log('#status: ', status);
console.log('#updatedPrice: ', updatedPrice);
useEffect(() => {
if (Object.keys(bodyQuery.values).length > 0) {
refetch();
}
}, [bodyQuery, refetch]);
export const getOptionsPrice = async (body: object) => {
try {
let response = await API.post('/filter/product/price', body);
return response.data?.detail?.price;
} catch (error) {
throw new Error(error);
}
};

So after some elaboration in the chat, this problem can be solved by leveraging the useQuery key array.
Since it behaves like the dependency array in the useEffect for example, everything that defines the resulted data should be inserted into it. Instead of triggering refetch to update the data.
Here the key could look like this: ['getUpdatedPrice', item.id, ...Object.keys(bodyQuery.values)], which will trigger a new fetch if those values change and on initial render.

Store data from useQuery with useState

I'm using React hooks both to fetch GraphQL data with react-apollo and to store local state:
const [userData, setUserData] = useState({})
const { loading, error, data } = useQuery(USER_QUERY)
However, I'm wondering how to store data to userData. Is this how it's supposed to work:
useEffect(() => {
setUserData(data)
}, [Object.entries(data).length])

Looks like what you have probably works. There is also a onCompleted option available in the options parameter. it takes a callback of type:
(data: TData | {}) => void
so this is another way of doing it:
const { loading, error, data } = useQuery(USER_QUERY, {onCompleted: setUserData})

What are you trying to do with the returned data that you are unable to accomplish by simply using it as destructured from the query hook? In most use cases it can be used immediately, as it will update itself when refetched.
If it is necessary (and it could be), as the other answer says, the useEffect hook you posted should work, but I would replace the dependency with simply data, to prevent an edge case where the response has an equal length consisting of different data and does not update:
useEffect(() => {
setUserData(data)
}, [data])

I think something like this would work - you will need to create the initial state with useState, could be empty array and then onComplete in the useQuery would setTranscationsData... it is triggered every render when state or props change. Could of course add an inital state inside useState which insn't an empty array.
const [transactionsData, setTransactionsData] = React.useState([]);
const { error, data } = useQuery(GET_TRANSACTIONS, {
onCompleted: () => {
setTransactionsData(data.transactions);
},
});
another example
const [getLegalStatement] = useLazyQuery(GET_LEGAL_STATEMENT, {
fetchPolicy: 'network-only',
onCompleted: (data) => {
setTempLegalStatement(data.getLegalStatement);
},
onError: () => {
setTempLegalStatement({
consentedLegalStatementHash: '',
consentedSuppliersHash: '',
statement: '',
suppliersModal: '',
});
setTimeout(() => {
setRefetchNeeded(true);
}, 10000);
},
});

Use onSuccess
const [userData, setUserData] = useState({})
const { data, isLoading, error } = useQuery('QueryKey', QueryFunction, { onSuccess: setUserData })
This onSuccess callback function will fire setUserData(data) for you automatically any time the query successfully fetches new data.

To elaborate above, you can't use onSuccess/onSettled because those will not rerun if the data is cached, so if you leave the component and come back before the query expires your data won't get set.

Relay Modern request onClick

How can i send a request to graphql using relay onclick ?
render(){
<div>
<img src={this.state.picture}>
<input type="email" value={this.state.email} onChange{...}/>
<button onClick={this.checkEmail}>Check</button>
</div>
}
checkEmail = async () => {
const res = await axios({
method: 'post',
url: __RELAY_API_ENDPOINT__,
data: {
query: `query CheckEmail($email: String!){lookupEmail(email: $email){id, picture}}`,
variables: {"email": this.state.email}
}
});
//set state using res
}
I cant figure out how to do this with relay.
In the examples relay is used to fetch and render onMount.
But how would i get data and change state on event listeners (onclick) ?
I couldnt find any example like that .

you can declare data dependency in relay but in some cases when you had a paginationcontainer which will fetch not 'all' e.g. first: 10 so we cannot get the length of it, in this case, you need to declare another data dependency by doing request. I hope you understand what I'm trying to say.
This is how i do it in my code, u need to explore the relay props more:
getPublicTodosLengthForPagination = async () => { // get publicTodos length since we cannot get it declared on createPaginationContainer
const getPublicTodosLengthQueryText = `
query TodoListHomeQuery {# filename+Query
viewer {
publicTodos {
edges {
cursor
node {
id
}
}
pageInfo { # for pagination
hasPreviousPage
startCursor
hasNextPage
endCursor
}
}
}
}`
const getPublicTodosLengthQuery = { text: getPublicTodosLengthQueryText }
const result = await this.props.relay.environment._network.fetch(getPublicTodosLengthQuery, {}) // 2nd arguments is for variables in ur fragment, in this case: e.g. getPublicTodosLengthQueryText but we dont need it
return await result.data.viewer.publicTodos.edges.length;
}
componentDidMount = async () => {
let result = await this.getPublicTodosLengthForPagination();
this.setState((prevState, props) => {
return {
getPublicTodosLength: result
}
});
}
implement this on ur code then update me.best of luck!