You can't do "branding" by properties on frozen objects. On Tue, 23 Apr 2019, 13:44 Andy Earnshaw, <[email protected]> wrote:
> This is pretty much what I used it for in a previous job role. We loaded > and unloaded various iframes, registering APIs and custom elements inside > them, adding the `window` object to a WeakSet so the initialisation only > ran once. > > On Tue, 23 Apr 2019 at 10:26, Andrea Giammarchi < > [email protected]> wrote: > >> WeakSet can be very useful in general to avoid *any* object to be >> visited/setup twice, not just those coming from user-land classes. >> >> Circular references, mixins, DOM nodes one-off events handling, and so on >> and so fort. >> >> On Mon, Apr 22, 2019 at 8:26 PM #!/JoePea <[email protected]> wrote: >> >>> (I edited the broken format of my previous post) >>> >>> What other use cases are there? >>> >>> On Mon, Apr 22, 2019 at 11:20 AM #!/JoePea <[email protected]> wrote: >>> >>>> > WeakSets are perfect for branding and are how I would expect web >>>> platform class branding to be explained. >>>> > >>>> > ```js >>>> > const foos = new WeakSet(); >>>> > >>>> > class Foo { >>>> > constructor() { >>>> > foos.add(this); >>>> > } >>>> > >>>> > method() { >>>> > if (!foos.has(this)) { >>>> > throw new TypeError("Foo.prototype.method called on an >>>> incompatible object!"); >>>> > } >>>> > } >>>> > } >>>> > ``` >>>> >>>> Just curious, is that effectively the same as what the (current) >>>> [private fields proposal](https://github.com/tc39/proposal-class-fields) >>>> offers? >>>> >>>> ```js >>>> class Foo { >>>> #isFoo = true >>>> >>>> method() { >>>> if (this.#isFoo) { >>>> throw new TypeError("Foo.prototype.method called on an >>>> incompatible object!"); >>>> } >>>> } >>>> } >>>> ``` >>>> >>>> - Joe >>>> >>> _______________________________________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
