How can I update a state variable from a promise?

Question

I am trying to determine if a customer has an active subscription or not. To do this I am utilizing the following code:

const stripe = require('stripe')('some-api-key');

export default function Example(){
    // the user will automatically be considered non-subbed by default
    const [isSubscriber, setIsSubscriber] = useState(false)


    // grab the customer id from stripe
    async function get_customer_id() {

        const customers = await stripe.customers.search({
            query: `metadata[\'some-meta-data-key\']:\'some-meta-data-value\'`
        });
        return customers.data[0]['id']
    }


    // grab the list of active subscriptions from stripe
    async function customer_is_subscriber(){
        const subs = await stripe.subscriptions.list({
            status: 'active',
        });
        return subs
    }


    // determine if the customer id is in the list of active subscriptions. 
    // return true if so, false otherwise
    async function test_equality(){
        const customer_id = await get_customer_id();
        const subbed = await customer_is_subscriber();

        const answer = subbed.find(sub => sub.customer === customer_id)
        return !!answer;
        
    }


    useEffect( () => {
        async function load_result() {
            const promise_function_return = await test_equality()
            setIsSubscriber(promise_function_return)
        }
        load_result();
}, [isSubscriber]);


return (

// some react code

)

}

I have been able to successfully get all of my other functions where I am doing the comparisons for if a user is a subscriber but where I am having an issue is updating the state value (e.g. true if they are subbed, false otherwise).

I found some good past questions on this specific topic such as: here The useState set method is not reflecting a change immediately

here: setState inside Promise in React

and here: setState inside a Promise function in a useEffect with hooks?

but I just have not been able to get it working correctly. This is currently the closest I have been able to get to solving this problem.

Answer 1

Currently your code says that, when isSubscriber changes, it should check if the user is a subscriber and update the isSubscriber state... so it's a chicken and egg problem. It won't set isSubscriber until isSubscriber gets set.

I think you want to change }, [isSubscriber]); to }, []); so that that code executes when the component first loads (not when isSubscriber changes).