Why can't I declare local variables and functions within a TypeScript class?

Question

In TypeScript, I can't seem to declare a function in a class without the compiler adding it to the prototype. For example:

class MyTypeScriptClass {
    // method, is added to prototype
    foo1(): void {
        alert('invoked foo1');
    }

    // private method also added to prototype
    private foo2(): void {
        alert('invoked foo2');
    }

    //// can I have a local function, without making it a private method?
    //function foo3() {
    //    alert('invoked foo3');
    //}
}

The above compiles to this:

var MyTypeScriptClass = (function () {
    function MyTypeScriptClass() { }
    MyTypeScriptClass.prototype.foo1 = function () {
        alert('invoked foo1');
    };
    MyTypeScriptClass.prototype.foo2 = function () {
        alert('invoked foo2');
    };
    return MyTypeScriptClass;
})();

What I am looking for is typescript that can compile to the following JavaScript:

var fvm = new FlasherViewModel2();
    var MyTypeScriptClass = (function () {
        function MyTypeScriptClass() { }
        MyTypeScriptClass.prototype.foo1 = function () {
            alert('invoked foo1');
        };
        MyTypeScriptClass.prototype.foo2 = function () {
            alert('invoked foo2');
        };
        function foo3() {
            alert('invoked foo3');
        }
        return MyTypeScriptClass;
    })();

Can it be done?

(As a side note, I know that foo3 would not be callable from external code. I would actually invoke foo3 from another method within the class, for example, to pass a function to a jQuery fadeOut.)

Answer 1

As apsillers mentions, private static is probably what you want. While it's not supported in current builds, you will be able to have a private static member in TypeScript at some point in the future (the design team changed its mind on this one based on feedback similar to this).