Question

I have the following error when running the page below:

“this.testpublic is not a function”

test = function() {
        var testprivate = function() {
                this.testpublic();
        }

        this.testpublic = function() {
                console.log('test');
        }

        testprivate();
}
new test();

Apparently when testprivate is called, “this” starts pointing to “window” instead of the object.

Shouldn’t JavaScript preserve “this” context when within the same object?

Answer 1

You need to manipulate the context when calling testprivate. You can use function.call to override the scope of the function. Try this:

test = function() {
        var testprivate = function() {
                this.testpublic();
        }

        this.testpublic = function() {
                console.log('test');
        }

        testprivate.call(this);
}
new test();