JavaScript losing “this” object reference with private/public properties

Question

I have the following error when running the page below:

\"this.testpublic is not a function\"

test = function() {
        var testprivate = function() {         


        

Answer 1

The problem is that this actually never was referring to the test object to begin with. It was always referring to the nearest enclosing object -- which in this case is window.

test = function() {
        var testprivate = function(say) {
                console.log('test', say);
        }

        this.testpublic = function(say) {
                testprivate('test', say);
        }

        testprivate();
}
x = new test();

This works because, as I understand it, this is determined at call time -- and it is locked into the nearest "enclosing" object*, unless call() or apply() is used.

* There is probably a much better word for this, but I don't know it off the top of my head. If someone knows, please enlighten us all :-)