--- id: useQueries title: useQueries --- The `useQueries` hook can be used to fetch a variable number of queries: ```tsx const ids = [1, 2, 3] const results = useQueries({ queries: ids.map((id) => ({ queryKey: ['post', id], queryFn: () => fetchPost(id), staleTime: Infinity, })), }) ``` **Options** The `useQueries` hook accepts an options object with a **queries** key whose value is an array with query option objects identical to the [`useQuery` hook](../useQuery.md) (excluding the `queryClient` option - because the `QueryClient` can be passed in on the top level). - `queryClient?: QueryClient` - Use this to provide a custom QueryClient. Otherwise, the one from the nearest context will be used. - `combine?: (result: UseQueriesResults) => TCombinedResult` - Use this to combine the results of the queries into a single value. > Having the same query key more than once in the array of query objects may cause some data to be shared between queries. To avoid this, consider de-duplicating the queries and map the results back to the desired structure. **placeholderData** The `placeholderData` option exists for `useQueries` as well, but it doesn't get information passed from previously rendered Queries like `useQuery` does, because the input to `useQueries` can be a different number of Queries on each render. **Returns** The `useQueries` hook returns an array with all the query results. The order returned is the same as the input order. ## Combine If you want to combine `data` (or other Query information) from the results into a single value, you can use the `combine` option. The result will be structurally shared to be as referentially stable as possible. ```tsx const ids = [1, 2, 3] const combinedQueries = useQueries({ queries: ids.map((id) => ({ queryKey: ['post', id], queryFn: () => fetchPost(id), })), combine: (results) => { return { data: results.map((result) => result.data), pending: results.some((result) => result.isPending), } }, }) ``` In the above example, `combinedQueries` will be an object with a `data` and a `pending` property. Note that all other properties of the Query results will be lost. ### Memoization The `combine` function will only re-run if: - the `combine` function itself changed referentially - any of the query results changed This means that an inlined `combine` function, as shown above, will run on every render. To avoid this, you can wrap the `combine` function in `useCallback`, or extract it to a stable function reference if it doesn't have any dependencies.