I can't consider `.last(1)` method to be readable... But I think `.nth(n)` method with support for negative index would be really useful.
2016-01-23 17:32 GMT+01:00 kdex <[email protected]>: > Not every feature addition is due to performance or paradigms. Just have a > look at ES2015: I'm sure that this has neither been the motivation for > `String.prototype.startsWith`nor for `String.prototype.includes`. Even > `String.prototype.repeat` appears so simple that a loop paired with a > concatenation could have become a popular alternative. > > Of course you could solve most of these string problems with earlier > versions > of the language, too, often explicitly thinking with incides. But on the > downside, your code suddenly becomes a potentially unintuitive, > index-ridden > mess, introducing off-by-one and out-of-bound errors (it even happened to > someone on this thread, too, if you review Thomas' code from above). This > isn't really all too much about saving keystrokes, but mainly about writing > clean, readable and maintainable code. > > There's array::back in C++, negative indices in Python as well as Bash or > end > in PHP, so I don't see any reason why we should complicate things for > people > coming from these languages. Nor to I see why we should torture ourselves > thinking about how the underlying data structure stores its elements > internally when all I care about is reading the last element. > > Just ask yourself: Do you think it's substantially more readable to write > > ```js > [1, 2, 3].slice(-2)[1]; > ``` > over > ``` > [1, 2, 3].last(1); > ``` > ? > > If it comes to write access, I agree that`Symbol.last` could be another > handy > addition (it doesn't have to be an "either/or" discussion, really): > > [1, 2, 3][Symbol.last]; // 3 > [1, 2, 3][Symbol.last] = 4; // 4 > [1, 2, 3].last(1); // 2 > > On Samstag, 23. Januar 2016 18:01:24 CET Bob Myers wrote: > > On Sat, Jan 23, 2016 at 12:54 PM, kdex <[email protected]> wrote: > > > [1, 2, 3].last(); // 3 > > > > I'm wondering what the ultimate motivation for suggestions like this is. > Is > > it to save key strokes? Allow more semantic coding? Support new > paradigms? > > Performance? 'm sure someone has already come up with a good > categorization > > like this, would someone mind providing a link? Could one of these be > > considered the "theme" for the next version? > > > > I have to admit to be being quite negative about proposals of the form > > "Hey, this other language does X, can we do that too?", or "It would be > so > > cool if we could do Y", especially when these are mostly about syntax. > Is a > > missing `last` really one of our painpoints? > > > > Bob > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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