BTW, all this is very much just a special case of this (existing stage 1) proposal, and is part of why it exists: https://github.com/tc39/proposal-partial-application
I do find it surprising that property access isn't addressed there, but it seems like it was likely just overlooked - it has no mention in the repo, in the open issues, or even in the closed issues or any of the open or closed pull requests. ----- Isiah Meadows cont...@isiahmeadows.com www.isiahmeadows.com On Tue, Dec 3, 2019 at 5:43 AM Michael Luder-Rosefield <rosyatran...@gmail.com> wrote: > > At the cost of adding more code, but giving more power, perhaps what we want > is something akin to Kotlin's `it` keyword: > https://kotlinlang.org/docs/reference/lambdas.html?_ga=2.238822404.500195435.1575368476-1345353619.1575368476#it-implicit-name-of-a-single-parameter > > it: implicit name of a single parameter > It's very common that a lambda expression has only one parameter. > If the compiler can figure the signature out itself, it is allowed not to > declare the only parameter and omit ->. The parameter will be implicitly > declared under the name it: > ints.filter { it > 0 } // this literal is of type '(it: Int) -> Boolean' > > > What we'd want is something concise and non-ambiguous to fulfill the same > role; something that cannot currently be a valid identifier, maybe. This is > the point where I start scanning the keyboard for underutilised symbols... > I'm thinking the hash symbol would work. To re-use the original example: > > ```js > const activeProducts = products.filter(#.active); > const productNames = products.map(#.name); > const sortedProducts = _.sortBy(products, #.name); > const { true: activeProducts, false: inactiveProducts } = _.groupBy(products, > #.active); > ``` > > It makes intuitive sense in 2 ways, I think; # makes you think of the object > hash you're extracting a property from, and also is familiar as something's > id from CSS selectors. > > We could also extend it to represent multiple parameters: # is also aliased > as #0, the 2nd parameter is #1, etc. > > Further, dynamic properties would work too: `const fooProducts = > products.filter(#[foo]); > -------------------------- > Dammit babies, you've got to be kind. > > > On Mon, 2 Dec 2019 at 22:32, Waldemar Horwat <walde...@google.com> wrote: >> >> On 11/24/19 9:17 PM, Bob Myers wrote: >> > FWIW, the syntax `.propName` does appear to be syntactically unambiguous. >> >> It conflicts with contextual keywords such as `new . target`. >> >> Waldemar >> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
