On Monday, January 7, 2013, Andrea Giammarchi wrote: > not always, only when thisArg is needed ... Array#reduce(cb, > initialValue[, thisArg]) > > if needed, arr.reduce(cb, undefined, obj) does not look that bad, IMHO >
undefined is a valid initialVal and won't cause reduce to fallback to the first item in the array (I'd that behaviour was desired). Effectively changing this: var array = [2,3,4]; array.reduce(cb.bind(ctx)) To: array.reduce(cb, array[0], ctx); Not worth it. In fact, it's not even clear now what that param is even for... var Rick > > again, I m fine with current status ... > > > On Mon, Jan 7, 2013 at 3:14 PM, Rick Waldron <waldron.r...@gmail.com>wrote: > > > > On Monday, January 7, 2013, Andrea Giammarchi wrote: > > thisArg could have been third optional argument leaving current > implementation as it is but making thisArg possible, IMHO > > > lucky me I don't use Array#reduce that much neither I need the thisArg so > far so ... OK for me > > > Sorry, but no—this would force user code to always provide an initialVal, > even when it would prefer to use the first item the array—which is the > default when initialVal is omitted. > > Rick > > > > > On Mon, Jan 7, 2013 at 2:59 PM, Rick Waldron <waldron.r...@gmail.com>wrote: > > > > On Monday, January 7, 2013, Andrea Giammarchi wrote: > > Rick you know bind is that slow and it costs on GC if used massively ;-) > > > This is not my problem, implementors should optimize. bind() would only > occur once per method call. > > > > I use a lot the second argument in Array#extras and I feel Peter van der > Zee here: reduce/Right should have had that too > > > The initialVal argument is _optional_ and undefined is valid — how would > you decide if what was passed should be initial value or thisArg? > > Rick > > > > > > > br > > > > > > > On Mon, Jan 7, 2013 at 1:10 PM, Rick Waldron <waldron.r...@gmail.com>wrote: > > I know this doesn't answer your question, but Function.prototype.bind > makes thisArg obsolete. > > Regarding the origin story, there is some discussion here: > https://mail.mozilla.org/pipermail/es-discuss/2008-June/006431.html > > Rick > > > On Mon, Jan 7, 2013 at 3:56 PM, Andrea Giammarchi < > andrea.giammar...@gmail.com> wrote: > > I think to increase confusion with other Array#extras :D > > and since we have this specced as it is now, a third parameter for the > context could add even more confusion later on <3 > > I know, I should not have answered that ... > > > On Sun, Jan 6, 2013 at 9:48 AM, Peter van der Zee <e...@qfox.nl> wrote: > > Mostly out of curiosity; why do Array#reduce and reduceRight have no > context parameter? > > - peter > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > > > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > h <https://mail.mozilla.org/listinfo/es-discuss> > >
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