I have gone through several questions and posts regarding how to accomplish this but none have worked. I have tried an array (no pun intended) of possible solutions involving Promise.*, thenable, await and none have worked.

I have an array of payments that I extract from a Prisma db call, the object looks like this:

[{
    "id": 1,
    "amount": 100,
    "payment_data": [{
        "credits": 2,
        "subscription_id": 534
    }, {
        "credits": 3,
        "subscription_id": 469
    }],
    "customerId": 14
}]

I am trying to run another database query using the subscription_id under each payment_data for which I built a simple function:

const get_subscription = async function (subscription_id) {
    return await db.subscriptions.findUnique({
        where: {
            id: Number(subscription_id)
        }
    })
}

And then I execute it inside a .map like this:

const mapped_payments = payments.map((payment) => ({
    ...payment,
    payment_data: payment.payment_data.map(function (data) {
        data.subscription = get_subscription(data.subscription_id).then((resp => resp))
        return data
    })
}))

The problem is no matter what I have tried this never resolves. If I console log mapped_payments the subscription object shows as Promise {<pending>} and entirely empty when I return the response in express.

I am sure this is a simple solution but I have moved all possible solutions (Promise.*, thenable, await) into the function, into the .map and into the res.send but none work.

Any help is appreciated!

CodePudding user response：

You need to use async map callback to await the get_subscription function, Also it would be better to use Promise.all to handle all mapped promises.

const mapped_payments = await Promise.all(payments.map(async (payment) => ({
    ...payment,
    payment_data: await Promise.all(payment.payment_data.map(async function (data) {
        data.subscription = await get_subscription(data.subscription_id)
        return data
    }))
})))