React-query useInfiniteQuery: getNextPageParam not working - reactjs

Question

I'm stuck using useInfiniteQuery.
The first call works fine, but the next page is not called with getNextPageParam
const getProductItems = async (par) => {
console.log("axios :", par);
const res = await axios.get(`/api/v1/products`, {
params: par,
});
return {
result: res.data,
};
};
export default function useGetProductItems(params) {
const { data, isLoading, fetchNextPage, hasNextPage, isFetching } =
useInfiniteQuery(
["getItems"],
({ pars = params }) => getProductItems(pars),
{
getNextPageParam: (res) => {
console.log(res);
const nextParams = {
...res.result.pageInfo,
page: res.result.pageInfo.page + 1,
};
console.log("next :", nextParams);
return nextParams;
},
select: (data) => {
return data.pages[0].result.data;
},
}
);
return {
data,
isLoading,
fetchNextPage,
hasNextPage,
isFetching,
};
}
And the Query Client setting is like this
export const queryClient = new QueryClient({
defaultOptions: {
queries: {
refetchOnWindowFocus: false,
},
},
queryCache: new QueryCache({
onError: errorHandler,
}),
mutationCache: new MutationCache({
onError: errorHandler,
}),
});
As I am new to react-query, I am also wondering if there is any data that must be received from the API.
plz answer for me

Answer 1

You can access pageParam and send it as argument to your fetching function. Also it'd be a good idea to check if there really is a next page before incrementing the actual page number in getNextPageParam. Something like this:
const { data, isLoading, fetchNextPage, hasNextPage, isFetching } =
useInfiniteQuery(
['getItems'],
({ pageParam = 1 }) => getProductItems(pageParam), // pageParam defaults to the first page
{
getNextPageParam: lastPage => {
return lastPage.result.pageInfo.page < lastPage.result.pageInfo.totalPages // Here I'm assuming you have access to the total number of pages
? lastPage.result.pageInfo.page + 1
: undefined // If there is not a next page, getNextPageParam will return undefined and the hasNextPage boolean will be set to 'false'
},
select: data => {
return data.pages[0].result.data
},
}
)
I don't have information about how is your API endpoint built, but typically the request should look, for example, like this:
const getProductItems = async (page) => {
const res = await axios.get(`/api/v1/products?page=${page}`);
return {
result: res.data,
};
};