On Apr 23, 2012, at 3:30 PM, Russell Leggett wrote: > > > That is only true for functions that actually use |this|. Even though bind > > is probably not used in force yet because of cross-browser worries, "var > > self = this" is used everywhere. Functions using that pattern are no more > > usable with call/apply than arrow functions. > > "everywhere" is incredibly strong wording, and I think that in the > large, you're probably not correct. Some large % of code might > manually "call their scope" through closure binding, but even that > isn't an argument against soft binding. > > Let me reword from "everywhere" to "extremely common". My point was that even > though it is not used in every case, it is used often enough that |this| > cannot be relied on. And my other point was that you have to know how the > function passed in *uses* this, which makes it pretty tightly coupled. > > > Last I checked, the new method form is still a dynamic binding - otherwise > > it wouldn't work. So really, you're just talking about arrow functions. In > > the cases where arrow functions make the most sense (callbacks) you rarely > > want a dynamic |this| - the oddball case being event handlers primarily. > > Having done this dance a couple of times, let me suggest to you that > the method form will *eventually* end up at a per-class getter on the > prototype which vends an instance function which is bound. People will > (reasonably) want binding of some sort. > > If that happens, then I will be more inclined to agree with you. Until that > happens, I guess I just don't. Your argument seems balanced on something > which you think will happen. I find that hard to agree with. > > > > I really just don't see the value of changing the |this| value of a function > > created for the purpose of being an argument to a function. And frankly, I > > just don't see many other use cases for arrows. Maybe thats the part I'm > > missing. > > Yeah, I think you're missing the composition arguments. If I create > mixins with methods, they're going to have a promiscuious "this" as a > *feature*. You might not write code like this today, but you probably > should ;-) > > I use mixins all the time, I just don't see them being being declared with > arrow functions, which was the point I was trying to make here. If you are > creating a mixin, then you would most likely want to use the new method > syntax or at least the function syntax, but I think it would be silly to use > the arrow function syntax, so I guess I'm just not sympathetic to that.
If methods on classes sprout binding of some sort, this will be the natural style. And I think that's a good place to be. If both arrow and class methods lexically soft-bind, truly unbound functions will be declared as "function" and will be easy to spot. _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
