If it's unfixably broken[1], non-extensible, excessively vague, and 
non-orthogonal, where does that leave you?

[1] <https://twitter.com/BrendanEich/status/798317702775324672>

From: Jordan Harband <[email protected]>
Sent: Saturday, July 27, 2019 3:00 PM
To: Michael Haufe <[email protected]>
Cc: ViliusCreator <[email protected]>; [email protected]
Subject: Re: Proposal: Typeof Trap

Those two PRs are about removing implementation-defined behavior from `typeof`, 
making it *more* reliable - there is no trend away from using and relying on 
`typeof`, full stop.

`Symbol.hasInstance` is a part of why `instanceof` is actually unreliable - 
because user code can hook into it. It would be a massive loss imo if `typeof` 
lost its bulletproof status by adding a user hook.

On Sat, Jul 27, 2019 at 12:37 PM Michael Haufe 
<[email protected]<mailto:[email protected]>> wrote:
The trend seems to be to rely on typeof less and less as time passes:

From the  March 2019 Agenda 
<https://github.com/tc39/agendas/blob/274e49412c09f81a0a82f386e6eead481c69adad/2019/03.md>:

“Implementation-defined typeof still necessary?” 
<https://github.com/tc39/ecma262/issues/1440>
“Normative: Remove implementation-defined typeof behavior” 
<https://github.com/tc39/ecma262/pull/1441>


The only real discussion around this I can find is from a related proposal from 
Brendan Eich a few years ago:

https://esdiscuss.org/topic/typeof-extensibility-building-on-my-value-objects-slides-from-thursday-s-tc39-meeting



From: ViliusCreator 
<[email protected]<mailto:[email protected]>>
Sent: Saturday, July 27, 2019 2:04 PM
To: Michael Haufe <[email protected]<mailto:[email protected]>>
Subject: RE: Proposal: Typeof Trap

Yes, but it traps `typeof `, not `instanceof`. There’s difference there.
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