In mongoDB using mongoose, get count of array elements

In mongoDB, get number of array items in a document — and why didn’t I just use sql to begin with!?

I have a document that looks like this …

{
    "age": 18,
    "role": "client",
    "email": "[email protected]",
    "name": "down",
    "answers": [{
        "_id": {
            "$oid": "61aa9a5e467fa9109b745d21"
        },
        "position": 2,
        "scale": 9,
        "slider": 0
    }, {
        "_id": {
            "$oid": "61aa9d3cd3912610d1196e40"
        },
        "position": 2,
        "scale": 9,
        "slider": 0
    }],
    "createdAt": {
        "$date": "2021-11-01T20:26:05.225Z"
    },
    "updatedAt": {
        "$date": "2021-12-03T22:42:04.861Z"
    },
    "__v": 0
}

Using mongoose, how do I get the number of array elements in the answers array?