React Native Deck Swiper - reactjs

Question

I am trying to make a GET request to an enpoint using the two functional components below to display in my react native deck swipper
//using fetch
const getDataUsingFetch = () => {
fetch(latestNews+ApiKey)
.then((response) => response.json())
.then((responseJson) => {
// set the state of the output here
console.log(responseJson);
setLatestNews(responseJson);
})
.catch((error) => {
console.error(error);
});
}
//using anxios
//asynchronous get request call to fetech latest news
const getDataUsingAnxios = async () => {
//show loading
setLoading(true);
setTimeout(async () => {
//hide loading after the data has been fetched
setLoading(false);
try {
const response = await axios.get(latestNews+ApiKey);
setLatestNews(response.data);
setLoading(false);
console.log(getLatestNews);
} catch (error) {
// handle error
alert(error.message);
}
}, 5000);
};
Data returned when logged from console:
Array [
Object {
"category_id": "8",
"content": "Hi",
"created_at": "2020-11-12T12:43:03.000000Z",
"featured_image": "splash-background_1605184983.jpg",
"id": 19,
"news_url": "doerlife.com",
"title": "I m good how about you",
"updated_at": "2020-11-12T12:43:03.000000Z",
}....]
I now save the data into a state array
const [getLatestNews, setLatestNews] = useState([]);
Here is my swipper(some code ommited - not necessary)
<Swiper
ref={useSwiper}
//cards={categoryID(docs, "2")}
cards={getLatestNews}
cardIndex={0}
backgroundColor="transparent"
stackSize={2}
showSecondCard
cardHorizontalMargin={0}
animateCardOpacity
disableBottomSwipe
renderCard={(card) => <Card card={card} />}
.....
When I try to access any data in the array from my Card reusable component, e.g card.featured_image
I WILL GET THIS ERROR - TypeError: undefined is not an object (evaluating 'card.featured_image').
PLEASE CAN SOMEONE HELP ME.
//Card reusable component for deck swipper
import React from 'react'
import { View, Text, Image, ImageSourcePropType } from 'react-native'
import styles from './Card.styles'
const Card = ({ card }) => (
<View activeOpacity={1} style={styles.card}>
<Image
style={styles.image}
source={card.featured_image}
resizeMode="cover"
/>
<View style={styles.photoDescriptionContainer}>
<Text style={styles.title}>{`${card.title}`}</Text>
<Text style={styles.content}>{`${card.content}`}</Text>
<Text style={styles.details}>
Swipe Left to read news in details
</Text>
</View>
</View>
);
export default Card

Answer 1

I've done something similar to this before so I think I can help a bit. The problem here is that your getLatestNews state has not been updated yet before the cards render. You can fix the problem by having another state called "isDataReturned". Then, have a useEffect that triggers whenever getLatestNews's length changes. If getLatestNews's length is > 0, then you can set isDataReturned to be true and render the deck only when isDataReturned is true.
Here's a code sample that I made:
const [getLatestNews, setLatestNews] = useState([]);
const [dataIsReturned, setDataIsReturned] = useState(false)
useEffect(() => {
const fetchData = async () => {
const result = await axios(
'https://cat-fact.herokuapp.com/facts',
);
setLatestNews(result.data);
};
fetchData();
}, []);
useEffect(() => {
if (getLatestNews.length > 0) {
setDataIsReturned(true)
} else {
setDataIsReturned(false)
}
}, [getLatestNews.length])
if( dataIsReturned === true) {
return (
<View style={styles.container}>
<Swiper
cards={getLatestNews}
renderCard={(card) => {
return (
<View style={styles.card}>
<Text>{card.text}</Text>
</View>
)
}}
onSwiped={(cardIndex) => {console.log(cardIndex)}}
onSwipedAll={() => {console.log('onSwipedAll')}}
cardIndex={0}
backgroundColor={'#4FD0E9'}
stackSize= {3}>
</Swiper>
</View>)
} else {
return(<Text>Loading</Text>)
}

Answer 2

In the renderCard attribute, i changed it from
renderCard={(card) => <Cardz card={card} />}
to
renderCard={(card) => (card && <Cardz card={card} />) || null}
and it worked.