Forgive me if I'm wrong, but the double-for comprehension (e.g. [for (i of numbers) for (j of letters) i + j]) can't be easily expressed in JS because there's no flatMap.
- Gil On Mon, Feb 6, 2017 at 7:17 PM T.J. Crowder <[email protected]> wrote: > Given `Array.prototype.filter`, `Array.prototype.map`, and other utilities > you can create combined with arrow functions, what is it about using syntax > for this instead that draws you? For me, the syntax doesn't add any > expressiveness, e.g. I don't see that this: > > ```js > const numbers = [1, 2, 3]; > const doubled = [for (i of numbers) i * 2]; > ``` > > is any more expressive than > > ```js > const numbers = [1, 2, 3]; > const doubled = numbers.map(i => i * 2); > ``` > > > How do you usually approach or avoid this issue? > > I use `filter`, `map`, and such. > > > Do you think we should look at improving and standardizing the > comprehension syntax? > > I don't see much percentage in it, FWIW, barring hearing more about the > motivations for having it. > > -- T.J. > > On Mon, Feb 6, 2017 at 4:59 PM, Ryan Birmingham <[email protected]> > wrote: > > Hello all, > > I frequently find myself desiring a short array or generator comprehension > syntax. I'm aware that there are functional ways around use of > comprehension syntax, but I personally (at least) love the syntax in the ES > reference ( > https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Array_comprehensions > ). > > The best previous discussion on this that I found was six years old ( > https://esdiscuss.org/topic/array-comprehensions-shorter-syntax) and > answers some of my questions, raising others. That said, I wanted to ask: > > - Why is the Comprehension Syntax in the reference yet not more > standard? It feels almost like a tease. > - How do you usually approach or avoid this issue? > - Do you think we should look at improving and standardizing the > comprehension syntax? > > > Thank you all for humoring me, > > -Ryan Birmingham > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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