Question

exports.list = function(callback){

  var result = model.find({}, function(err, objects){
    callback(null, objects)
  });
  return result;
}

Q: Why is the above code a closure? Is it because the function parameter calls the function callback which is nested in it?

Q: does this cause an infinite loop, since the function is calling itself through its parameter?

Q: will the above function work if callback wasn’t defined anywhere?

Answer 1

Q: Why is the above code a closure? Is it because the function parameter calls the function callback which is nested in it?

A: As Mike explained, once an outside var is used inside a function, you create a closure.

Q: does this cause an infinite loop

A: I assume function(err, objects) will fire only once for the model, so no it won’t. You would create an infinite loop if you call callee (or self)

Q: will the above function work if callback wasn’t defined anywhere?

A: you will get an error ReferenceError: callback is not defined