Hide picked items in a FlatList

Question

I'm using react-native FlatList to render out a punch on elements the data of which comes from an external API.

I want to prevent the user from picking the same item twice. So the way I'm going about this it hiding the item after they pick it.

If, let's say, I have a state picked like so

  const [ picked, setPicked ] = useState(false);

changing it will of course hide all the elements.

      <FlatList
        {/*some other props*/}
        data={allCards}
        renderItem={(card: ListRenderItemInfo<CardsProps>) => (
          <TouchableOpacity
            style={[ styles.holder, { display: picked ? "none" : "flex" } ]}
            onPress={() => handleChoice(parseInt(card.item.id))}
          >
            <Card
             {/*some card props*/}
            />
          </TouchableOpacity>
        )}
      />

How can I go about changing the state for only one element inside the FlatList?? Is there a better approach you would recommend to do the same job?

Answer 1

try it like this, it will work,

<FlatList
        {/*some other props*/}
        data={allCards}
        renderItem={(card: ListRenderItemInfo<CardsProps>) => picked ? (
          <TouchableOpacity
            style={[ styles.holder, ]}
            onPress={() => handleChoice(parseInt(card.item.id))}
          >
            <Card
             {/*some card props*/}
            />
          </TouchableOpacity>
        ): undefined}
      />

Answer 2

The easiest way to do this is if you create an object with all the ids and while inserting it you can check it whether it's in that list or not it'll cost u O(1) time to check.

<FlatList
    {/*some other props*/}
    data={allCards}
    renderItem={(card: ListRenderItemInfo<CardsProps>) => picked ? (
      <TouchableOpacity
        style={[ styles.holder, ]}
        onPress={() => handleChoice(parseInt(card.item.id))}
      >
        <Card
         {/*some card props*/}
        />
      </TouchableOpacity>
    ): undefined}
  />
const map=new Map();
    const handleChoice=(id)=>{
if(Map.get(id)===undefined){
Map.set(id,true)
//add the element to ur list where u need it to
}
    }