Catchall invocation for 'null' and 'undefined' (or: how to be a disruptive influence in 3 easy steps)

William Edney bedney at
Fri May 15 10:45:25 PDT 2009

All -

I sent this about 1.5 weeks ago, but have gotten no responses. I can  
attribute this to 2 possible items:

1. I made the mistake of replying to an existing message so this one  
got buried under a thread it shouldn't have.

2. Folks were so horrified as to what I was asking for that they  
really just wished I would go away :-).

I'll repeat the message here. If the answer is #2, please let me know  
and I'll crawl back under my rock :-).


- Bill

All -

Well, Sister Eugenia always did say I was a disruptive influence in  
grade school - guess I haven't changed much :-).

Let me throw another idea into the mix and churn the pot a bit more.

Many moons ago when I was a Smalltalker, I always liked the fact that  
'nil' in Smalltalk was a singleton instance of UndefinedObject... and  
you could add methods to UndefinedObject :-).

Like... doesNotUnderstand.

When I switched to JS, I found out that 'null' and 'undefined' were  
'special' and weren't instances of anything I could add methods to  
(cue wailing and gnashing of teeth).

I always thought it would be most interesting if the following were  
true: 'null' was the singleton instance of the Null type and  
'undefined' was the singleton instance of the Undefined type.

Then, I could do the following (which would have saved me a lot of  
debugging time over the years):

(Using the older __noSuchMethod__ syntax):

Null.prototype.__noSuchMethod__ = function (id, args)
alert('you were a bad boy and tried to send ' + id + ' to null');

Undefined.prototype.__noSuchMethod__ = function (id, args)
alert('you were a bad boy and tried to send ' + id + ' to undefined');

My business partner Scott has bugged Brendan about this in the past  
and he mentioned that ES3 was too set in its ways to do anything like  
this, but I figured maybe with Harmony on the horizon, the issue could  
be revisited :-). I have no idea regarding the implications of such a  
change and therefore leave it to you all to consider those implications.



- Bill

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