javascript - Node js custom callback function error -

i'm trying make simple authentication node js. because read user data database, have make asynchronous. here's function, checks if authentication ok:

function auth(req, callback) {     var header = req.headers['authorization'];     console.log(cb.type);     console.log("authorization header is: ", header);     if(!header) {         callback(false);     }     else if(header) {          var tmp = header.split(' ');         var buf = new buffer(tmp[1], 'base64');         var plain_auth = buf.tostring();         console.log("decoded authorization ", plain_auth);         var creds = plain_auth.split(':');         var name = creds[0];         var password = creds[1];          user.findone({name:name, password:password}, function(err, user) {             if (user){                 callback(true);             }else {                 callback(false);             }         });                 }        } 

and here call function:

auth (req, function (success){                     if (!success){         res.setheader('www-authenticate', 'basic realm="myrealm');         res.status(401).send("unauthorized");     }else{                                      if(user!==req.user) {             res.status(403).send("unauthorized");         }else{             user.findoneandupdate({user:userid}, {user:req.body.user, name:req.body.name, email:req.user.email, password:user.generatehash(req.body.password)},             {upsert:true}, function(err, user) {                 if(!err) {                     res.status(200).send("ok");                 }else{                     res.status(400).send("error");                 }             });         }     } }); 

this gives me error "typeerror: object not function", pointing @ "callback(false)". have no idea cause error, pass function parameter, , first log message prints "[function]". appreciated.