how to do subquery in formatter

[warrior7789]

`Model.dataTables({ limit: input.length, skip: input.start, search: { value: req.body.search.value, fields: ['name'] }, sort: orderBy, formatter: function(table) { let permission_html = ""; _.each(table.permission,function(p){ permission_html = permission_html + ""+ p.name +"" })

        var count = 0 
            count = await Admin.countDocuments({'roles':table._id}).exec() 
        console.log("count")
        console.log(count)

        return {
            actions     : '<a href="/admin/role/update/'+table._id+'"><i class="fas fa-edit"></i></a><a data-id="'+table._id+'" href="javascript:void(0)" class="delete_role"><i class="fas fa-trash"></i></a>',
            id          : table._id,
            _id         : i++,
            name        : table.name,
            permission  : permission_html,
            created_at  : moment.unix(table.created_at).format("DD-MM-YYYY H:s"),
        }            
    }        
}).then(function (table) {
    /*console.log("table")
    console.log(table)*/
    table.draw = table.draw
    table.recordsTotal = table.total
    table.recordsFiltered = table.total
    res.json(table); // table.total, table.data
})`

i want count how much admin hase this role