I had this hunch that it was out there somewhere...hmm thank you guys! I do agree default parameters, and default destructuring values is the way to go.
On Mon, Feb 10, 2014 at 6:08 AM, Brendan Eich <[email protected]> wrote: > Good memory. This is all at esdiscuss.org in the meeting notes, but I > can't google for ||= to save my life, even in Verbatim mode. Anyone? > > Of course the original proposal is still in strawman stage on the wiki: > > http://wiki.ecmascript.org/doku.php?id=strawman:default_operator > > /be > > Domenic Denicola <mailto:[email protected]> >> February 9, 2014 at 12:49 PM >> >> There was very active discussion, probably around 1.5 years ago, about >> `||=` vs. a proposed `?=` (where `x ?= y` ≈ `x = x !== undefined ? x : y`). >> >> From what I recall some of the major points of discussion were: >> >> - Should `?=` use `undefined` as its sentinel, or work with either `null` >> or `undefined`? (This was before the behavior for default parameters was >> decided.) >> - Would adding `||=` be an attractive nuisance, when people "should" be >> using `?=` instead? >> - Given the existence of default parameters, and default destructuring >> values, are either of these even necessary? >> >> The last point, I think, was what killed both `?=` and `||=`. They become >> much less necessary when you can write things like >> >> ```js >> function f(foo = true, { bar = 5, baz = "ten" } = {}) { >> console.log(foo, bar, baz); >> } >> ``` >> >> From: es-discuss [mailto:[email protected]] On Behalf Of >> Andrea Giammarchi >> Sent: Sunday, February 9, 2014 15:29 >> To: Hemanth H.M >> Cc: es-discuss >> Subject: Re: shorthand notation for attribute creation? >> >> Unless I misunderstood your idea, `||=` makes me naturally think about >> `+=` so if >> >> `i += n;` means `i = i + n` >> >> then >> >> `o.name ||= value` means `o.name = o.name || value` >> >> and this would be, according with all these years in ES3, the least >> surprising behavior which is **way different** from checking if `name` is >> not defined. >> >> Accordingly, I wonder ... >> 1. what if `name` was inherited with a non _falsy_ value ? >> 2. what if `name` was defined as `undefined` ? >> 3. should that silently fail if `name` was already defined ? >> Cheers >> >> >> >> >> On Sun, Feb 9, 2014 at 2:17 AM, Hemanth H.M <[email protected]> wrote: >> Something like `var foo = {}; foo.bar ||= 3` would be very useful. >> But not sure how something like `obj['name']['maxlength']` be reduced to >> shorthand check if 'name' is not defined. >> >> >> >> >> Andrea Giammarchi <mailto:[email protected]> >> February 9, 2014 at 12:29 PM >> >> Unless I misunderstood your idea, `||=` makes me naturally think about >> `+=` so if >> >> `i += n;` means `i = i + n` >> >> then >> >> `o.name <http://o.name> ||= value` means `o.name <http://o.name> = o.name< >> http://o.name> || value` >> >> >> and this would be, according with all these years in ES3, the least >> surprising behavior which is **way different** from checking if `name` is >> not defined. >> >> Accordingly, I wonder ... >> >> 1. what if `name` was inherited with a non _falsy_ value ? >> 2. what if `name` was defined as `undefined` ? >> 3. should that silently fail if `name` was already defined ? >> >> Cheers >> >> >> >> >> >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >> > -- *'I am what I am because of who we all are'* h3manth.com <http://www.h3manth.com> *-- Hemanth HM *
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