Callbacks in Javascript

.js

function getUser(userID, callback) {
	/* This is a hypothetical function. Normally we'd talk to a database or so, but this is to illustrate the concept... */
	var someUser = {name: "Joe Bloggs", age: 42};
	callback(someUser); /* Here we call the callback from the second function argument, with our fake user */
}

/* Code: */
getUser(42, function(user){
	/* Now `user` contains {name: "Joe Bloggs", age: 42} */
});

/* We could also write this as: */
function whenDone(user) {
	/* Now `user` contains {name: "Joe Bloggs", age: 42} */
}

getUser(42, whenDone);

@diogocapela No because he's simulating a DB call.

It would normally be:

var someUser = db.getUserById(userID);

But instead he's just creating an object and pretending that's what he looked up with the userID.

It would probably be clearer if he made use of that getUser function he created though.