TypeError: Cannot read properties of undefined (reading 'type')-CodePudding

I'm trying to do a balance of incomes/expenses at my budget admin app and i keep getting this error at my balance component: TypeError: Cannot read properties of undefined (reading 'type').

I think the problem may be related with the state I bring from my reducer that comes duplicated, 2 times with an empty array [] and 2 times full. I tried a lot but couldn't fix it.. any idea what it could be??

This is my balance component code:

export default function Balance(){

    const operations = useSelector((state) => state.operations);

    console.log(operations);
    //Shows 4 arrays, 2 empty and 2 full

    const [total, setTotal] = React.useState([]);

    const operationsListCopy = [...operations];

    React.useEffect(() => {

        let entryArray = operationsListCopy.filter((oneOperation) => oneOperation.type == 'INCOME');
        let entryArrayTotal = entryArray?.reduce((amount, item) => item.amount   amount, 0);

        let exitArray = operationsListCopy.filter((oneOperation) => oneOperation.type == 'EXPENSE');
        let exitArrayTotal = exitArray?.reduce((amount, item) => item.amount   amount, 0);
            
        let arrayTotal = entryArrayTotal - exitArrayTotal;

        setTotal(arrayTotal);
    }, [operations]);

CodePudding user response：

You should check for null or undefined value before accessing it. you could add condition here

let entryArray = operationsListCopy.filter((oneOperation) => oneOperation?.type == 'INCOME');

and here

 let exitArray = operationsListCopy.filter((oneOperation) => oneOperation?.type == 'EXPENSE');