AS3 -TypeError #1009 - any easy way to find out *which* object reference is null?

Answer 1

TypeError will not give you any more information if you catch it.

As far as I know, there is no known way to achieve this (i.e which object threw the Error).

Your best bet will be to set a breakpoint in the beginning of the function and investigate the variables manually. That's what I do, and that works fairly well for me.

Answer 2

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

Answer 3

The obvious solution is to stop using such generic error-prone code in the first place. You should never use '*' type, and almost never should use 'Object' type.

To catch it at runtime, you could always say:

if(obj == null)
  throw new Error("null obj passed in!!");

if(obj.nonExistentProperty == null)
  throw new Error("obj doesn't have the prop!! the obj was: "+obj);