On Tue, Oct 7, 2014 at 12:25 PM, Dmitry Soshnikov < dmitry.soshni...@gmail.com> wrote:
> On Tue, Oct 7, 2014 at 12:22 PM, Rick Waldron <waldron.r...@gmail.com> > wrote: > > >> >> On Tue, Oct 7, 2014 at 3:01 PM, Dmitry Soshnikov < >> dmitry.soshni...@gmail.com> wrote: >> >>> On Tue, Oct 7, 2014 at 11:59 AM, Dmitry Soshnikov < >>> dmitry.soshni...@gmail.com> wrote: >>> >>>> On Tue, Oct 7, 2014 at 11:56 AM, Claude Pache <claude.pa...@gmail.com> >>>> wrote: >>>> >>>> >>>>> >>>>> >>>>> > Le 7 oct. 2014 à 20:36, Dmitry Soshnikov <dmitry.soshni...@gmail.com> >>>>> a écrit : >>>>> > >>>>> > And other things are better be written: >>>>> > >>>>> > ``` >>>>> > <ArrayKind>.from(iterable).map(mapfn) >>>>> > ``` >>>>> > >>>>> > Am I still missing something? >>>>> >>>>> Yes: `UInt32Array.from(['a', 'b', 'c], x => x.codePointAt(0))` >>>>> >>>>> >>>> Still seems the same as `NodeList` "issue": >>>> >>>> ``` >>>> UInt32Array.from(['a', 'b', 'c].map(x => x.codePointAt(0))); >>>> ``` >>>> >>> >>> And after you have fed the data the `UInt32Array` expects, you can >>> post-map it as well: >>> >>> >>> ``` >>> UInt32Array.from(['a', 'b', 'c].map(x => x.codePointAt(0))).map(v => v * >>> 2); >>> ``` >>> >>> What's is wrong in here? >>> >> >> That example will allocate 2 additional objects; the following version of >> the same operation will allocate _zero_ additional objects: >> >> UInt32Array.from(['a', 'b', 'c], x => x.codePointAt(0) * 2); >> >> > Exactly. And this is what I mentioned at the beginning: the performance > reasons shouldn't (never) overweight in "good API design" topics. > > Since the next question will be: where is filter? It allows not allocating stuff at all. However, we won't mention whether it's an anti-pattern or not, since it goes without saying. Dmitry
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