Problem with javascript ( Array is automatically converted to string )

Hello all : )

I have a very strange problem...

so I have an object like this:

{
 "1": [ {...}, {...} ],
 "2": [ {...}, {...}, {...} ]
}

and so on. these keys are IDS. so I want to get the current array with ID

const getFirstArray = myObjectWithArrays[ID]

so if ID is 1 it will return the first array of objects. and it's working well. but the next step is that I need to generate an excel file with this data. Am using the XLSX library to generate an excel file.

XLSX.utils.json_to_sheet(data)

in data, u must add an array of objects. it's working with other arrays but when I am adding an array like this myObjectWithArrays[ID] Am getting error "carr[1].forEach is not a function" I searched and found info that

"using numbers as property names in JavaScript objects can sometimes cause unexpected behavior since they can be automatically converted to strings."

I really need to fix this problem... Please can anyone help me with this?