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
