Question

I’m working on a short JavaScript program, which works perfectly fine ONLY if I inject any trivial statement–such as var asd;–at a specific location. The program is intended to demonstrate a simple encapsulation technique.

No other locations work. ANY trivial statement works.
This is not a DOM load issue since I’m not even dealing with the DOM.

version that works: (warning, 3 alerts)
http://jsfiddle.net/bZUm6/3/

version that does not work:
http://jsfiddle.net/bZUm6/2/

Please note the “var asd;” in the first version.

Can someone please tell me why?
I would really appreciate it.

Max

Answer 1

It’s the semicolon removal that’s breaking it.

It will work even if you change…

var asd;

simply to this…

;

The reason is that the next line of code starts with (, which happens to be wrapping a function with its closing ).

This is being interpreted as a function call operator, and is attempting to invoke the previous expression.

    MyApp.util.toXML = function(options, obj) {
        // your code

        return result.join("");
    }

//    var asd;   // removing the semicolon

//  |------seen as invoking the result of the previous expression and passing
//  v         the function as an argument. 
    (function(toXML) {

        // your code

    })(MyApp.util.toXML);
//     ^---------------^ This is then attempting to invoke the return value
//     of "toXML", which if it successfully returned, returned a String, which 
//     can't be invoked.