newbie here

let useDB = (action) =>{
    MongoClient.connect(url, (err, db)=>{
        if(err) throw err;
        let currentDB = db.db("mydb");
        let currentCol = currentDB.collection("items");

        let getData = ()=>{
            currentCol.findOne({}, (err, res)=>{
                if(err) throw err;
                return res <--- problem here
            })
        }
        if(action === "FIND") return getData()
    })
}

console.log(useDB("FIND"));

gives undefined while

let useDB = (action) =>{
    MongoClient.connect(url, (err, db)=>{
        if(err) throw err;
        let currentDB = db.db("mydb");
        let currentCol = currentDB.collection("items");

        let getData = ()=>{
            currentCol.findOne({}, (err, res)=>{
                if(err) throw err;
                console.log(res); <--- problem here
            })
        }
        if(action === "FIND") return getData()
    })
}

useDB("FIND")

works, this is a problem as i want the function to have the value of the data and not just log it to the console