How do I update a single data in an array with react native firestore?

Question

My Purpose: When the onPress operation occurs, the followCategory value found in the id I clicked should be false if true, and true if false.Firestore Update single item in an array field

How can I find the id of the button I clicked?

 const dbStore = firebase.firestore();
 export default Kategoriler = () => {

  const [list, setList] = useState([]);
  
  const fireStore = dbStore.collection('Agar').doc('Kategoriler');
  
  function getCategory(){

    fireStore.get().then((docSnapshot)  =>{

      if(docSnapshot.exists){

      
            const data=docSnapshot.data().follow;
            const categoryList=Object.values(data) || [];
            console.log(data);
            setList(categoryList);
      } 
      
    })
  }
  
  useEffect(() => {
    
  
    getCategory();
    
    
    
    },[]);

  
        return (
            <SafeAreaView style = {styles.container}>
               
            <FlatList
            showsVerticalScrollIndicator={false}
            style = {styles.cat}
            data = {list} 
            keyExtractor = {item => item.idkey}
            renderItem = {({item,index}) => (
            
              <View style = {styles.catItem}>
             
                <TouchableOpacity>
                <Image source = {{uri: item.image}} style = {styles.loggo}/>
                </TouchableOpacity>
                <View style={{flex:1}}>
                    <View style = {{flexDirection: "column" , 
                    justifyContent: "space-around" , 
                    alignItems: "center"}}>
                        <View>    
                        <Text style = {styles.name}>{item.name}</Text>
                        <Text style = {styles.text}>{item.postCount}</Text>
                        </View>
                    </View>
                </View>
                <View>
                        <Image style = {{width: 30 , height: 30 , marginTop: 4 }}
                        source = {{uri: 'https://ibb.co/L5WY5X2'}} />
                        </View> 
                        <View>
            <TouchableOpacity 
            
          onPress={
            
              ()=>{
                 fireStore.update({
                    followCategory:!item.followCategory,
                  
                  
                 });
                
              }

            }
              >
              <Icons
              name={item.followCategory ? 'heart' : 'heart-o'}
              size={20}
              color={'#E02401'}
              
              
              />

             
            </TouchableOpacity>
            </View>
            </View>
            )}
            >
           
            </FlatList>

            </SafeAreaView>
        );
    }

This firestore data, Update single item in an array field

Answer 1

You should get a copy of your array from your database, then update whatever you want to change and upload it again.

Make sure to merge the document, not to replace it by using

yourDoc.set({follow: newArray}, {marge: true})

Answer 2

Call this method on onPress

const followNextState = list.map((item, idx) => {
  if (index === idx) {
    return ({...item, followCategory: true})
  } else return item
})

firestore.update({follow: followNextState})