Merge map values

Andrea Giammarchi andrea.giammarchi at gmail.com
Tue Apr 28 12:58:56 UTC 2015


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 <axel at rauschma.de> 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 <andrea.giammarchi at gmail.com>
> 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 <zenparsing at gmail.com> 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.
>>
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>>
>>
>
> --
> Dr. Axel Rauschmayer
> axel at rauschma.de
> rauschma.de
>
>
>
>
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