typeof null

Brendan Eich brendan at mozilla.org
Wed May 9 14:22:15 PDT 2012

As Crock said, the problem programmers face is "I have a value, I want 
to treat it as an object and get a property (call a method, etc.). How 
do I test is-this-an-object so that I can use dot without worrying about 
that throwing right away on null left-hand side?"


John J Barton wrote:
> On Tue, May 8, 2012 at 6:07 PM, Brendan Eich<brendan at mozilla.org>  wrote:
>> Object class reflection is frowned upon in Smalltalk for a reason. We want
>> protocols, structural conventions -- not nominal type tags. Or so I think!
> Perhaps it would be helpful if someone made the case for typeof null
> === 'null'.
> To me typeof null === 'object' is fine. It makes null a value in the
> space of 'object'. In practice I see 'null' used to mean "I know this
> reference (usually an argument) should be an object; I want to pass
> nothing but signal that I really did mean to pass nothing." The status
> quo allows this and it seems enough work for null to do for us.
> Are there new things I can do if I now have a new answer to the
> 'typeof' question?
> jjb
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