Can’t perform a React state update on an unmounted component.React useEffect Error

I want to dispatch orderDetails from firestore. This code works when page load first time,but if i refresh page i got an error.

    useEffect(() => {
    const getUserOrders=()=>{
     const shopdbRef=doc(db,"shopDB",user?.uid);
     const userOrderRef=getDocs( collection(shopdbRef,"userOrderInfo"))
     .then(response=>(
       response.docs.map((doc)=>{
         dispatch({
           type:"ADD_TO_ORDERS",
           item:{
             id:doc.id,
             data:doc.data()
           }
         })
       })
     )).catch(error=>{
         console.log(error.message)
     })
    }
    getUserOrders();
  }, []);

error>>>>>>>>>>>>>

 Warning: Can't perform a React state
 update on an unmounted component. 
 This is a no-op, but it indicates a 
 memory leak in your application.
 To fix, cancel all subscriptions 
 and asynchronous tasks in a useEffect
 cleanup function.

I am new to react.js can anyone help me
as shown in the error what actually cleanup means,And how can i implement cleanup in my case.