Darien Maillet Valentine

@michaelficarra is there somewhere one could learn more about that / see the discussion?

Re: churn, outside ES repos it looks like IsCallable is used by at least the following specs & proposals: [HTML](https://html.spec.whatwg.org/) [Web Audio](https://webaudio.github.io/web-audio-api/) [Web IDL](https://webidl.spec.whatwg.org/) [WebAssembly JSI](https://webassembly.github.io/spec/js-api/) [WebAssembly JSI Exception Handling](https://webassembly.github.io/exception-handling/js-api/)...

This seems to nearly retain the flexibility of current WeakMap solutions and can be reasoned about in the same terms, which I like very much. One thing I don’t understand:...

> the only reasonable scenario for brand-checking is some security stuff Security is not the only reason to perform brand checks, but I don’t think it’s a significant factor since,...

Polyfilling APIs defined by Web IDL is probably the most common, but also just in ordinary library code that wishes to establish very strict invariants. Just as one might be...

@littledan I think that’s true. But from my perspective, “private name declarations outside classes” is the key thing. What continues to make me nervous about the current proposal is mainly...

@zenparsing regarding bullet 2, I see that as a positive facet of this proposal, since being able to do something inadvertently is an unavoidable consequence of being able to do...

In addition to the use of WeakSet for brand checks, if I understand correctly, wouldn’t private symbols still permit them with a small helper? ```js const brandCheck = (obj, key)...

Thanks for the explanation, makes sense! In some cases for me where I currently use strict weak collection brand checks, I have no reason to disallow a proxy from "counting,"...

(You may want to edit the second example btw, I think there’s a reference error in the third statement.)