How can I index nested array fields without views in CouchDb?

Question

I'm looking for index a nested array field, I have the following document:

{
    "id": "invoice1",
    "sellers": [{
        "names": "Clark",
        "items": [{
            "iditem": "item1",
            "properties": [{
                "width": "212cm"
            }]
        }]
    }]
}

How can I index Width field?

I already tried sellers.items.properties.width

I have read about partial index but if I create a partial index with elemMatch and $eq it will be static.