How to map nested array in javascript(node.js) API?

Question

let getOeReport = async (req, res) => {
    try {
       
        let searchFormatForReason = {
            "query": {

                "reasonCode": null,

            },
            "fields": {
                'reason': 1, '_id': 0
            }
        }
        let result = await oeDao.getOeReport(searchFormat)

        let resultReasons =
            result.map(async res =>
                res.sequences.map(inter =>
                    inter.interrupts.map((interrupts) => {
                        searchFormatForReason.query.reasonCode = interrupts.reason
                        reasonDao.getReasonByFields(searchFormatForReason)

                    })
                )
            )
        console.log(resultReasons)
        res.status(200).json({
            status: "Success",
            data: {
                result: result
            }
        });
    } catch (err) {
        console.log(err)
        res.status(400).json({
            status: "Failure"
        });
    }
};

Here in the above code, If I try to console the resultReasons means I'm getting null. Result variable has nested array of objects so that, I need 'reason' value inside interrupts array which is inside sequences array and that is within the result array. And i should make API request with that value and I could push it into resultReasons array. Please someone help me... Thank You

Answer 1

let resultReasons =
        result.map(async res =>
            res.sequences.map(inter =>
                inter.interrupts.map((interrupts) => {
                    searchFormatForReason.query.reasonCode = interrupts.reason
                    reasonDao.getReasonByFields(searchFormatForReason)

                })
            )
        )

In this piece of your code you are using async so you must be receiving a Promise , since you are not making use of await within that async function I don't see the reason of keeping it, however you can just add an await as per the code below and should fix the issue ( you are already using async on getOeReport so it will work without any modifications )

let resultReasons =
        await result.map(async res =>
            res.sequences.map(inter =>
                inter.interrupts.map((interrupts) => {
                    searchFormatForReason.query.reasonCode = interrupts.reason
                    reasonDao.getReasonByFields(searchFormatForReason)

                })
            )
        )

But you are saying you get null which I don't understand how you are getting it, this because again you are using an async function within the first map, hence you must get a Promise , the only way I see your variable can be null is if the result variable is null, BUT it should trigger an Exception so your console.log will never be excecuted