Flatlist not updating when the data is changed - react-native

Question

I have an issue when I update the item's Quantity then set array, FlatList is not Updating
also, extraData is not working for me I have tried so many things to fix it, but still not working
check the code for adding quantity function below:
const handleAdd = (message) => {
//add Quantity for items
let items = list;
let index = items.findIndex((el) => el._id == message._id);
items[index] = {
...items[index],
sellingQuantity: parseInt(items[index].sellingQuantity) + 1,
};
setList(items);
};
and here is the FlatList
<FlatList
data={list}
keyExtractor={(message) => message._id}
renderItem={({ item }) => (
<ListItemSelling
title={title}
barcode={item.barcode}
description={item.description}
price={item.price1}
quantity={item.sellingQuantity}
totalPrice={item.totalPrice}
renderLeftActions={() => (
<View style={styles.swipeLeft}>
<TouchableOpacity onPress={() => handleDelete(item)}>
<MaterialCommunityIcons
name="trash-can"
size={30}
color={colors.white}
/>
</TouchableOpacity>
</View>
)}
renderRightActions={() => (
<View style={styles.swipeRight}>
<TouchableOpacity onPress={() => handleAdd(item)}>
<MaterialCommunityIcons
name="plus"
size={30}
color={colors.white}
/>
</TouchableOpacity>
<TouchableOpacity onPress={() => handleDeduct(item)}>
<MaterialCommunityIcons
name="minus"
size={30}
color={colors.white}
/>
</TouchableOpacity>
</View>
)}
/>
)}
/>

Answer 1

I fixed it by adding another function to count total
const countTotal = () => {
let element = 0;
for (let i = 0; i < list.length; i++) {
element += list[i].totalPrice;
}
setTotalItems(element);
console.log(element);
};
then adding countTotal(); in the handleAdd() function