React Native How to output typeerror undefined is not a function (*near '?

Question

JSON

componentDidMount() {
        fetch(URL)
          .then(response => response.json())
          .then(d => this.setState({ data: d.result, isLoading: false}))
      }

Here is the json I received

{
    "result": {
        "0": {
            "id_audio": 456239297,
            "artist": "M83",
            "title": "Wait",
            "duration": 341,
            "album": {
                "id": 283748,
                "title": "Hurry up, We're Dreaming",
                "owner_id": -2000283748,
                "access_key": "f93158b94b047c185d",
                "thumb": {
                    "width": 300,
                    "height": 300,
                    "photo_34": "https://sun9-23.userapi.com/c846420/v846420866/1b7cdd/N9UXljP4rbM.jpg",
                    "photo_68": "https://sun9-8.userapi.com/c846420/v846420866/1b7cdb/vaNasR5grv8.jpg",
                    "photo_135": "https://sun9-35.userapi.com/c846420/v846420866/1b7cd9/JEv0ezslpzo.jpg",
                    "photo_270": "https://sun9-58.userapi.com/c846420/v846420866/1b7cd6/SeaXxgNn3DM.jpg",
                    "photo_300": "https://sun9-29.userapi.com/c846420/v846420866/1b7cd4/ZgRTpPVt0Ko.jpg",
                    "photo_600": "https://sun9-3.userapi.com/c846420/v846420866/1b7cd3/5BAvVADMyIg.jpg",
                    "photo_1200": "https://sun9-28.userapi.com/c846420/v846420866/1b7cd2/4logqCXt7E4.jpg"
                }
            }
        },
        "1": {
            "id_audio": 456239296,
            "artist": "Oxxxymiron",
            "title": "В книге все было по-другому (4 раунд, 17ib)",
            "duration": 355,
            "album": {
                "id": 6654357,
                "title": "В книге все было по-другому (4 раунд, 17ib)",
                "owner_id": -2000654357,
                "access_key": "5b15c63fb1b129ddf9",
                "thumb": {
                    "width": 300,
                    "height": 300,
                    "photo_34": "https://sun9-3.userapi.com/c205124/v205124138/57095/j9CB7aYfU1U.jpg",
                    "photo_68": "https://sun9-37.userapi.com/c205124/v205124138/57093/1bRMy1XGPJY.jpg",
                    "photo_135": "https://sun9-19.userapi.com/c205124/v205124138/57091/CuO5nkGfQEo.jpg",
                    "photo_270": "https://sun9-57.userapi.com/c205124/v205124138/5708e/wTY8MRva6FQ.jpg",
                    "photo_300": "https://sun9-25.userapi.com/c205124/v205124138/5708c/qFjYJeiDdnk.jpg",
                    "photo_600": "https://sun9-49.userapi.com/c205124/v205124138/5708b/x0BrDxrcpjY.jpg",
                    "photo_1200": "https://sun9-2.userapi.com/c205124/v205124138/5708a/0iVF5FNxbis.jpg"
                }
            }
        }
    }
}

This is how I take it out

const { isLoading, data } = this.state;

        if (isLoading) {
           return( <Text>Загрузка</Text>);
        }else{
            const Result = data.map((item) => {
                <Text>{item.title}</Text>
            });
            return( <Result/>);
        }
       
        return(
            <View style={styles.TrackList}>
                <isLoading/>
            </View>
        );

If you access the element directly

const {  data } = this.state;
alert(data[0].title)

it will output "Wait"

Answer 1

You don't have an array, but an object. Get around like this:

const Result = Object.keys(data).map((key) => {
               const item = data[key];
               return  <Text>{item.title}</Text>
            });