Would `new Map(maps.reduce((e, m) => e.concat(Array.from(m)), []))` not create a new Map from merging an array of `maps`? (It relies on the `Map.prototype.[Symbol.iterator]` which is `Map#entries`, and the `iterable` argument of the `Map` constructor)
On Tue, Apr 28, 2015 at 6:06 AM, Andrea Giammarchi < [email protected]> wrote: > Sorry Axel, I was rushing, it sounded over-rude ... so, yes, Map are > better for words, **but** in this specific case it was about all > chars/surrogate pairs, that's why I've said Objects where safe ... plus the > rest, reduce also is very handy for this exact kind of things ;-) > > But yes, if it was a owrd counter, I'd use same logic with new Map passed > instead of {} and the correct .set/.get invoke > > Best Regards > > On Tue, Apr 28, 2015 at 2:02 PM, Andrea Giammarchi < > [email protected]> wrote: > >> Moreover `undefined|0` is exactly 0. The `|0` is used in asm.js because >> it explicitly declares the intent. >> >> So again, no error in there ;-) >> >> Regards >> >> On Tue, Apr 28, 2015 at 1:58 PM, Andrea Giammarchi < >> [email protected]> wrote: >> >>> Now you read again the "exercise" and realize that's impossible to have >>> as a piutfall ... no, I just used a KISS approach for what I can tell, no >>> pitfalls with one single surrogate could happen by specs. >>> >>> Best Regards >>> >>> On Tue, Apr 28, 2015 at 1:57 PM, Axel Rauschmayer <[email protected]> >>> wrote: >>> >>>> With Maps, there are less pitfalls. For example: what if you want to >>>> use your version to count words and one of the words is `__proto__`? Most >>>> pitfalls can be fixed via `Object.create(null)`, but Maps are more >>>> straightforward for data (vs. code). >>>> >>>> But your version can be easily adapted to Maps, I like the way you use >>>> `reduce()`. The `|` should be a `||`. >>>> >>>> On 28 Apr 2015, at 14:31 , Andrea Giammarchi < >>>> [email protected]> wrote: >>>> >>>> Not sure why everyone went for the `Map` version when in JS every >>>> object is basically the equivalent of a `Map` already :-) >>>> >>>> ```js >>>> let m = Array.from("mainn").reduce((m,k) => ((m[k] = 1 + (m[k] | 0)), >>>> m), {}); >>>> ``` >>>> >>>> looks a win to me, if you need to check or drop chars from the string I >>>> would probably do it once before passing that to `Array.from` >>>> >>>> Agreed with Kevin this is rather a StackOverflow like question :-) >>>> >>>> Best Regards >>>> >>>> >>>> On Tue, Apr 28, 2015 at 1:19 PM, Kevin Smith <[email protected]> >>>> wrote: >>>> >>>>> Another option: >>>>> >>>>> var map = new Map; >>>>> Array.from("mainn") >>>>> .map(c => c.toLowerCase()) >>>>> .forEach(c => map.set(c, (map.get(c) | 0) + 1)); >>>>> >>>>> This kind of question is probably better left for StackOverflow, >>>>> however. >>>>> >>>>> _______________________________________________ >>>>> es-discuss mailing list >>>>> [email protected] >>>>> https://mail.mozilla.org/listinfo/es-discuss >>>>> >>>>> >>>> >>>> -- >>>> Dr. Axel Rauschmayer >>>> [email protected] >>>> rauschma.de >>>> >>>> >>>> >>>> >>> >> > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > >
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