When we use $lookup in aggregate query of MongoDB we use this format

{
   $lookup:
     {
       from: "users",
       localField: "userId",
       foreignField: "_id",
       as: "user"
     }
}

where user return as an array of object and then some time we need to use $arrayElemAt in $project stage to return as a single object. like

{
  $project:
   {
    user:
      { 
        $arrayElemAt: [ "$user", 0 ] 
      }
   }
}

so my request is can create option to return user as a single object instead of array from $lookup stage ?