Too many rerednders error by trying to show a FlatList-CodePudding

I am trying to display a flatList of numbers like this : (image of what the flat list would look like) To do that I did an array of objects with a numberName and a key, it's generating with a loop:

const number = 5;

let [numbers, setNumbers] = useState([]);

let nums = [];
for (let i = 0; i < number; i  ) {
nums.push({ numberName: i, key: i });

console.log(nums)
}
setNumbers((numbers) => [...numbers, ...nums]);

I dont think the problem is in the loop, but react is recalling the loop without showing the component. This makes an infinite loop and I have the too Many rerender error.

Here is what console.log(nums) shows (screenshot of the console)

and here is how i am trying to render the array :

if(!fontsLoaded) {return <AppLoading />} 
else {return (
    <View>
        <FlatList
            showsHorizontalScrollIndicator={false}
            horizontal={true}
            data={numbers} //la data qu'on va afficher
            renderItem={({ item }) => (
                <Text style={styles.number}>{item.numberName}</Text>
            )} //la fonction qu'il va rendre
        />
    </View>
)}

Why do I have the too many rerenders error and how do I fix it ?

CodePudding user response：

let [numbers, setNumbers] = useState([]);
useEffect(()=>{
const nums = numbers.map((value,index)=> {numberName: index,key: index})
setNumbers([...numbers, ...nums])
},[])

You need to do assignment/state-related stuff inside useEffect hook.

CodePudding user response：

const number = props.numberProp;

let [numbers, setNumbers] = useState([]);

useEffect(() => {    
let nums = [];
    for (let i = 0; i < number   100; i  ) {
    nums.push({ numberName: i, key: i });
    }
setNumbers((numbers) => [...numbers, ...nums]);
}, [])