react native fetch JSON, undefined is not an object

Question

== UPDATE ==

I have a problem with the feth of a JSON, I'm getting a JSON from google maps (this is the code) but I find it undefined.

    const [isLoading, setLoading] = useState(true);
    const [info, setInfo] = useState([]);

    const getInfo = () => {
        fetch(`https://maps.googleapis.com/maps/api/place/nearbysearch/json?place_id=${resturant.id}&$"'privatekey'"`)
          .then((response) => response.json())
          .then((json) => setInfo(json))
          .catch((error) => console.error(error))
          .finally(() => setLoading(true));
    }
    useEffect(() => {
        setLoading(false);
        getInfo();
    }, []);

    return(
        <View style={style.card}>
            {
            !isLoading ? <Text>LOADING</Text> :
                <View style={{
                flexDirection: "row",
                justifyContent: "space-between",
                marginTop: 10
            }}>
                <Text>{info.result.name}</Text> //this is the problem
            </View>
            }
        </View>
    )

JSON return

Error Message

Instead of providing screenshots provide the actual snippets of your code. Also, you have uploaded the code screenshots twice and neglected to upload the error message. Please update your question — Rob Terrell
– Rob Terrell, Commented Aug 23, 2022 at 18:15

Rob Terrell · Accepted Answer · 2022-08-24 13:11:01Z

1

const [isLoading, setLoading] = useState(false);
    const [info, setInfo] = useState([]);

    const getInfo = () => {
        fetch(`https://maps.googleapis.com/maps/api/place/nearbysearch/json?place_id=${resturant.id}&$"'privatekey'"`)
          .then((response) => response.json())
          .then((json) => setInfo(json))
          .catch((error) => console.error(error))
          .finally(() => setLoading(false));
    }
    useEffect(() => {
        setLoading(true);
        getInfo();
    }, []);

    return(
        <View style={style.card}>
            {
            isLoading ? <Text>LOADING</Text> :
                <View style={{
                flexDirection: "row",
                justifyContent: "space-between",
                marginTop: 10
            }}>
                <Text style={{fontSize: 16, fontWeight: "bold"}}>{resturant.nome}</Text>
                <Text style={{fontSize: 16, fontWeight: "bold"}}>{resturant.id}</Text>
                <Text>{info?.result?.name}</Text> //Update to utilize optional chaining
            </View>
            }
        </View>
    )

I am assuming the some of the objects do not contain the same level of information. Because of this, opt to use optional chaining to account for some of your result objects either missing or not containing a name like I am doing above.

EDIT

instead of optional chaining you could also update your initial state of your isLoading state to be true initially, there is no reason for it to be initially false. This will in turn ensure that your JSX will not render the info.result.name until the fetch request is completed.

edited Aug 24, 2022 at 13:11

answered Aug 23, 2022 at 23:19

Rob Terrell

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4 Comments

k0uh0t Over a year ago

I think this is good solution. JSX is rendered before data is fetched. That's why info is undefined.

Rob Terrell Over a year ago

@k0uh0t ah you’re right, didn’t realize initial state was an empty array

Tommaso Ceredi Over a year ago

thanks for your answers, so what would the optimal solution be?

Rob Terrell Over a year ago

@TommasoCeredi I have updated my answer to show two options that should work

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