The problem is the same unless you have a way of "gluing" an expression as a "shorthand-function" e.g. `:.prop1 / :.prop2` won't be interpreted as a single function that performs x.prop1 / x.prop2, but rather an attempt to perform division with 2 functions
On Wed, 26 Jun 2019 at 10:44, Michael Luder-Rosefield < rosyatran...@gmail.com> wrote: > The more I read this proposal, the more I feel the ideal solution is a > preceding 'wildcard' character, to stand-in for a generic argument. If it > wasn't in (widespread!) use, I'd suggest an underscore: ```const f = _.prop > ``` > > Since it is, though, we need another one. How about a double-colon, seeing > as it can represent property access on other languages? ```const f = > ::prop ```, ```const g = ::[compProp] ```, ```const h = ::?optProp ``` > > On Sun, 23 Jun 2019, 11:43 Simon Farrugia, <simonfarrugi...@gmail.com> > wrote: > >> I was expecting that someone brings up the brackets property accessor at >> some point. >> I would argue that there is a bit of syntactic inconsistency since >> usually when using the bracket accessors it is not preceded by a dot. >> ``` >> const getEmail = user => user["contacts"].email; // No dot between user & >> ["contacts"]. >> const getEmail = .["contacts"].email; >> ``` >> Having said that, the currently proposed Optional Chaining operator >> (Stage 2) <https://github.com/tc39/proposal-optional-chaining/> does >> exactly that and more: >> ``` >> obj?.prop // optional static property access >> obj?.[expr] // optional dynamic property access >> func?.(...args) // optional function or method call >> ``` >> So I'd say that there is consistency with what is currently being >> proposed. >> >> Regarding the Optional Chaining operator, which precedes the dot. How >> would that work? >> >> It would have to be something like this, if allowed. >> ``` >> >> const getEmail = user => user?.contacts.email; >> const getEmail = ?.contacts.email; >> >> ``` >> >> It does look odd at first, but it’s quite simple is you think about it. >> We are just omitting the initial part of the expression. >> >> >> >> More Examples with Optional Chaining operator: >> >> ``` >> >> // With optional dynamic property access. >> >> const getUserEmail = user => user?.["contacts"].email; >> const getUserEmail = ?.["contacts"].email; >> >> >> >> // With optional function or method call. >> >> const getJohnsEmail = getUserContacts => getUserContacts >> ?.("John").email; >> const getJohnsEmail = ?.("john").email; >> >> ``` >> >> >> >> The beauty of what is being proposed is that there is nothing new to >> learn or any new weird operator introduced. >> >> Any weirdness one might find with the expressions above will already have >> been introduced by the Optional Chaining operator. >> >> The only thing this does is to allow you to omit the initial (redundant) >> part of the expression. >> >> >> _______________________________________________ >> 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 >
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