Yes Michael, the `::` operator is the best thing ever proposed and got killed / pseudo replaced by another, completely different, operator that won't solve problems `::` would: the `|>` pipe one.
I'm a big fan of the `::` operator, and if it were there, I would quite possibly also like the "per context" restructuring. On Thu, Jul 19, 2018 at 5:12 PM Michael Luder-Rosefield < [email protected]> wrote: > At this point I can't ignore how much overlap there is between this and > the this-binding operator proposal > https://github.com/tc39/proposal-bind-operator > > ``` > const resolve = ::Promise.resolve; // takes and binds > ``` > > As someone who often extracts functions with deconstruction, I'd love for > there to be an extension to this proposal to handle this case. > > ``` > const { resolve, reject } = ::Promise; // ? > ``` > > That would leave the question though of what to do with nesting: > > ``` > const { fn1, foo: { fn2 } } = ::bar; // fn1 is bound to bar. Is fn2 bound > to bar, or foo? > ``` > > On Thu, 19 Jul 2018 at 15:58 Andrea Giammarchi < > [email protected]> wrote: > >> I guess one example would be more explicative: why cannot public static >> methods be defined in a similar manner? >> >> ```js >> const withLazyBoundObjects = new WeakMap; >> const withLazyBoundMethods = obj => { >> const descriptors = Object.getOwnPropertyDescriptors(obj); >> Object.keys(descriptors).forEach(key => { >> const desc = descriptors[key]; >> const {value} = desc; >> if (desc.configurable && typeof value === 'function') { >> delete desc.value; >> delete desc.writable; >> desc.get = function (...args) { >> let methods = withLazyBoundObjects.get(this || obj); >> if (!methods) >> withLazyBoundObjects.set(this, methods = Object.create(null)); >> return methods[key] || (methods[key] = value.bind(this)); >> }; >> } >> }); >> return Object.defineProperties(obj, descriptors); >> }; >> >> // example >> const {resolve, reject} = withLazyBoundMethods(Promise); >> resolve(123).then(console.log); >> ``` >> >> On Thu, Jul 19, 2018 at 4:33 PM Andrea Giammarchi < >> [email protected]> wrote: >> >>> sorry, that'd be `public get resolve()` and also `public #resolve()` so >>> nobody should be confused about the fact I'm talking about public static >>> methods. >>> >>> On Thu, Jul 19, 2018 at 4:32 PM Andrea Giammarchi < >>> [email protected]> wrote: >>> >>>> I know it's about subclassing, which is why I've asked why, once >>>> there's no context, the default/base one is not considered, but since >>>> everyone came back with the subclassing issue, which is actually what I've >>>> said myself on twitter about the current state, how about changing all >>>> public static methods that need it, to be getters ? >>>> >>>> ```js >>>> class Promise { >>>> #resolve(...args) { >>>> return this.nativeImplementation(...args); >>>> } >>>> get resolve() { >>>> return #resolve.bind(this); >>>> } >>>> } >>>> ``` >>>> >>>> we could argue `Promise.resolve === Promise.resolve` should be >>>> preserved, as behavior, so that we need a lazy defined getter ... **but** >>>> why not making public static restructuring from known constructors work >>>> regardless, under all circumstances ? >>>> >>>> >>>> On Thu, Jul 19, 2018 at 4:11 PM T.J. Crowder < >>>> [email protected]> wrote: >>>> >>>>> On Thu, Jul 19, 2018 at 12:56 PM, Andrea Giammarchi >>>>> <[email protected]> wrote: >>>>> > Why cannot Promise methods fallback to Promise constructor when the >>>>> > class/context is not available? >>>>> >>>>> That sounds reasonable on first glance, but I'd be concerned about >>>>> what happens when you do it after subclassing: >>>>> >>>>> ```js >>>>> class MyPromise extends Promise { >>>>> // ...and adds some important feature... >>>>> } >>>>> // ... >>>>> const {resolve, reject} = MyPromise; >>>>> const p = resolve(); >>>>> p.someImportantFeature(/*...*/); // TypeError: undefined is not a >>>>> function >>>>> ``` >>>>> >>>>> ...since `resolve` fell back to `Promise`. That feels like a footgun. >>>>> Either subclassers would have to handle that, which they will forget to >>>>> do, >>>>> or it has to be a bit more complicated than just a simple fallback to ` >>>>> Promise` (I don't immediately know what that "more complicated" >>>>> answer would be.) >>>>> >>>>> -- T.J. Crowder >>>>> >>>>> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> >
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