[SOLVED] VirtualizedList missing keys for items on React Native

KeyExtractor with react native flatList are a way each list in the item is identified by our flat list. Here is a quick solution if you encounter such an error while build a react native app.

VirtualizedList: missing keys for items, make sure to specify a key or id property on each item or provide a custom keyExtractor.
 <FlatList
        contentContainerStyle={styles.list}
        data={allItems}
        numColumns={2}
        renderItem={({item}) => (
          <Fragment key={item.toString()}>
            <Items />
          </Fragment>
        )}
        keyExtractor={(item) => item.toString()}
/>