javascript - Can't use non-anonymous method with socket.io, "listener" argument must be a function -

i searched answer (simple ?) question, yet, can't find clear.

i'm java developper trying fit in web market, but, oop, many things infurate me.

io.sockets.on('connection', function (socket) {     console.log("client has connected! id = [" + socket.id + "]");      socket.on('disconnect', onplayerdisconnected(socket)); });  function onplayerdisconnected(socket) {     socket.broadcast.emit('player_disconnected', socket.id);      console.log("client has disconnected! id = [" + socket.id + "]"); } 

here's stacktrace :

events.js:219     throw new typeerror('"listener" argument must function');     ^  typeerror: "listener" argument must function 

if use anonymous function, works charm. problem is, if react (increasing) number of events, code won't maintenable.

so, there way break down code smaller functions ?

bonus question : possible event split code in multiple .js files ?

thanks lot,
node.js beginner.

you're passing in result of function onplayerdisconnected (which appears undefined since nothing returned) socket.on('disconnect') handler , not actual function onplayerdisconnected looking for.

change below code passes result of onplayerdisconnected(socket)

socket.on('disconnect', onplayerdisconnected(socket));

to code passes actual function onplayerdisconnected

socket.on('disconnect', onplayerdisconnected);