It's impossible to add new methods on Object.prototype because it would be web-breaking - I have seen code that test for typeof arr.map === 'function'
On Set topic, I have written basic proposal for this <https://github.com/Ginden/set-methods>, but it was ignored so I didn't write formal spec. On 17/03/17 13:36, James Treworgy wrote: > I think a good solution that doesn't require new syntax would be > map/filter methods on the Object prototype that return a new object, > e.g. > > let subset = { a:1, b:2, c:3 }.filter(([key])=>['b'].includes(key)) > // subset = { b: 2 } > > let subset = { 1:1, b:2, c:3 }.map(([key, value])=>[key, value * 2]) > // subset = { a:2, b:4. c:6 } > > Actually I'd like this to be available on Map too. I've always thought > it was interesting that the Map and Set objects do not natively > include map/filter operations -- or maybe even most of the Array > prototype methods as applicable. And for Sets, basic set operations > like except/distinct/union. > > But a Javascript object is just a Map, really, or I guess one could > say that a Map is just an object with a few enhancements. It's > surprising that there is no native operation built in to directly > convert between Maps and objects given their conceptual similarity. In > either case though it would be nice to be able to apply standard > processing rules that one applies to Maps conceptually to an Object > (and a Map) natively, like filter and map. > > > > On Fri, Mar 17, 2017 at 8:04 AM, Felipe Nascimento de Moura > <[email protected] <mailto:[email protected]>> wrote: > > Hi. > Interesting to know that it has already been discussed. > > I know we could create a function to do similar things, but I > think the language itself has evolved so well, this is a use case > it could fit somehow. > > I think there could be different approaches for that, like > > Object.pick([ 'a', 'c' ], { a: 1, b: 2, c: 3 }) > > or > > let x = {a, c}{ a: 1, b: 2, c: 3 } > > or > > let {a, c} as x = { a: 1, b: 2, c: 3 } > > or > > > let x = { a: 1, b: 2, c: 3 }{a, c} > > or > > let x = { a: 1, b: 2, c: 3 }['a', 'c'] > > Would you consider any of those as an interesting option? > > thanks. > > > > On Fri, Mar 17, 2017 at 7:25 AM, peter miller > <[email protected] <mailto:[email protected]>> wrote: > > Hi, > > There seems to be little appetite for taking it up, in > spite of it being > (IMHO) a very common use case. > > > I'll second it being common in my code. My personal highlights > would be assigning to this: > > ``` > this.{x,y,z} = a; > ``` > > and combining it with property spreading: > > ``` > const result = { a, b, ...x.{ y, z }, ...p.{ q, r } }; > ``` > > Peter > > -- > "There were drawings, and sheets of paper with writing on > them, and it seemed that they were the sustenance of life, > that here were the warlocks, almost the vehicles of > destruction of man's life, but at the same time the very > reason for his living." --- Maeve Gilmore/Titus Awakes. > > _______________________________________________ > es-discuss mailing list > [email protected] <mailto:[email protected]> > https://mail.mozilla.org/listinfo/es-discuss > <https://mail.mozilla.org/listinfo/es-discuss> > > > > > -- > [ ]s > * > * > *--* > * > * > *Felipe N. Moura* > Web Developer, Google Developer Expert > <https://developers.google.com/experts/people/felipe-moura>, Founder > of BrazilJS <https://braziljs.org/> and Nasc <http://nasc.io/>. > > Website: http://felipenmoura.com <http://felipenmoura.com/> / > http://nasc.io/ > Twitter: @felipenmoura <http://twitter.com/felipenmoura> > Facebook: http://fb.com/felipenmoura > LinkedIn: http://goo.gl/qGmq > --------------------------------- > *Changing the world* is the least I expect from myself! > > _______________________________________________ > es-discuss mailing list > [email protected] <mailto:[email protected]> > https://mail.mozilla.org/listinfo/es-discuss > <https://mail.mozilla.org/listinfo/es-discuss> > > > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss
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