Question

We all get “TypeError #1009 Cannot access a property or method of a null object reference” now and then – no big deal, but sometimes frustrating to debug.

Flash gives you the call stack (which is a start), but leaves it up to you to figure out where the null object is – is it possible to find out exactly which reference is throwing the error?

Given the following (error prone) function:

function nullObjectReferenceError():void
    {
        var obj:Object;
        var prop:* = obj.nonExistentProperty;
    }

Rather than just the call stack from the TypeError, I’d like to trace something like: “Cannot access a property or method of a null object reference at obj.nonExistentProperty” – Is this even possible?

Answer 1

If you check Permit Debugging under Publish Settings in the Flash IDE, it gives you the line number in your code causing the error.