indeed as breaking new syntax anyway I'd rather use destructuring avoiding any possible ambiguity on `||=`
On Sun, Feb 9, 2014 at 12:49 PM, Domenic Denicola < [email protected]> wrote: > 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. > > > > > -- > 'I am what I am because of who we all are' > h3manth.com > -- Hemanth HM > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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