Js how to set an item at a nested index in an empty array [duplicate]

I have this array that has to be filled with objects. Each object has a slug with 4 sections divided by "-" (for example: test-dx-ef-1) and depending on it I have to place them in an array at a specific index named with the slug section.

I tried looping all the inputs and directly setting the object like so:

var data = []
objects.forEach((obj) => {

    var slug = obj.slug.split('-')
    data[slug[0]][slug[1]][slug[2]][slug[3]] = obj

}

But it didn't work, as apparently, even if data[slug[0]] can be created, data[slug[0]][slug[1]] results undefined and an error is thrown.

Is there a way in which I can accomplish this?