Mongoose - Increment a value inside an array of objects (of user id inside object)

Question

I have followed this

and my code looks like this

const updateAttendance = await privateClass.findOneAndUpdate({classId:req.body.classId,"attendance.date":date},
                {$inc:{`attendance.$.${user.id}`: 1 }})

the problem is -

`attendance.$.${user.id}` 

this line produce errors.

'user' is the object of JWT verification and I want to icncerement user.id by 1 inside object in attendance array. the document looks like this -

_id:ObjectId(some Id)
classId: 'id'
attendance:[
   {
   date:(value of Date.now()),
   userId_1:0,
   userId_2:0,
   .
   .
   .
  },
  {...},
  {...},
]