Question

I’m working with a pattern that looks like so (pseudo example):

var FOO = (function(foo) {

    var foo = foo || {},
    setThis = 'someValue';

    //--------------------------------------------------------------------------
    //
    // Public methods:
    //
    //--------------------------------------------------------------------------

    foo.init = function(bar) {

        this.blah = [];

        // Constructor stuff here...

    };

    foo.doSomething = function(bar) {

        if (bar) {

            this.doSomethingElse();

            // Stuff here...

        }

    };

    foo.doSomethingElse = function() {

        // Stuff here...

    };

    //--------------------------------------------------------------------------
    //
    // Private methods:
    //
    //--------------------------------------------------------------------------

    foo._imPrivate = function() {

        // ... stuff here ...

        this.blah = xyz; // References this.

    };

    foo._morePrivate = function(el) {

        // No reference to this.

    };

    foo._otherPrivate = function(el) {

        // No reference to this.

    };

    return foo; // Expose the methods.

}(FOO || {}));

Instanciated like so:

window.onload = function() { FOO.init(stuff); }

Three questions:

1. If my “private” methods don’t reference this, should I just make them “standard” functions (i.e. function _imPrivate() { ... }, for example)? Reason why I ask: I have a few methods that reference this, but I don’t want to give them public access; I also have a few “utility” methods that don’t reference this… Can the methods that reference this be standard functions (in context of the module pattern)?
2. Could someone provide an example of how I would implement a setter for the setThis variable?
3. Do you see any room for improvements in the above code?

Answer 1

1.

You can do _imPrivate.call(this, arg1, arg2,...);

And in this case this in the _imPrivate function will refer to the particular instance.

2.

var setThis = 'someValue';

foo.setter = function(value) {
    setThis = value;
};