classes and enumerability

Brendan Eich brendan at
Fri Jan 30 10:00:37 PST 2015

Please drop the crappy "us" vs. "them" talk. If you read this thread, 
and others on, you can see "TC39" did not "keep ignoring 
feedback". Yeesh!

We (TC39 includes web developers, W3C TAG members, WHATWG members and 
cofounders, all well-connected to others working with and on WebIDL) 
chose to align class prototype method enumerability with ECMA-262 core 
language built-in method enumerability and clearly-voiced developer 
expectations, against the old DOM enumerable-method norm, with the 
intention to bend WebIDL default that way where possible and provide 
decorator-based or better opt-out in the future.

It's not the end of the world that we live with further differences that 
have long stood between core language and browser method enumerability. 
What would be worse in our judgment: enumerability by default.


Anne van Kesteren wrote:
> On Fri, Jan 30, 2015 at 7:44 AM, Andrea Giammarchi
> <andrea.giammarchi at>  wrote:
>> Developers have to understand they cannot `new HTMLDivElement()` anyway and
>> they cannot extend WebIDL interfaces in JS world neither.
> That will change.
> bz and others have been working on bridging the gap for quite a while
> now. It's rather frustrating TC39 keeps ignoring the feedback given
> while at the same time complaining that DOM and IDL are so different.

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