JavaScript module pattern: How do private methods access module's scope?

Question

When implementing the module pattern, how do private functions access the private properties of the module? I haven't seen any examples where developers do this. Is there any reason not to?

var module = (function(){
    // private property
    var number = 0;

    // private method
    _privateIncrement = function(){
        // how do I access private properties here?
        number++;
    };

    // public api
    return {
        // OK
        getNumber: function(){
             return number;   
        },
        // OK
        incrNumber: function(){
             number++;  
        },
        // Doesn't work. _privateIncrement doesn't have
        // access to the module's scope.
        privateIncrNumber: function(){
            _privateIncrement();
        }
    };
})();

Answer 1

When implementing the module pattern, how do private functions access the private properties of the module?

The properties are in scope, so they "just do"

Doesn't work.

Yes, it does.

_privateIncrement doesn't have access to the module's scope.

Yes, it does.

See live example of the following:

var module = (function(){
    // private property
    var number = 0;

    // global method
    _privateIncrement = function(){
        number++;
    };

    // public api
    return {
        // OK
        getNumber: function(){
             return number;   
        },
        // OK
        incrNumber: function(){
             number++;  
        },
        // Does work!
        privateIncrNumber: function(){
            _privateIncrement();
        }
    };
})();

// Show default value
document.body.innerHTML += (module.getNumber());
// Increment
module.privateIncrNumber();
// Show new value
document.body.innerHTML += (module.getNumber());
// Increment (since _privateIncrement was defined as a global!)
_privateIncrement();
// Show new value
document.body.innerHTML += (module.getNumber());

// Output: 012