On Wed, May 30, 2012 at 1:32 PM, Allen Wirfs-Brock <[email protected]>wrote:
> > On May 29, 2012, at 10:05 PM, Rick Waldron wrote: > > > On Wednesday, May 30, 2012 at 12:00 AM, Russell Leggett wrote: > > > > On Tue, May 29, 2012 at 11:52 PM, John Tamplin <[email protected]> wrote: > > On Tue, May 29, 2012 at 11:50 PM, Yehuda Katz <[email protected]> wrote: > > I'm not sure if this makes sense, but something about breaking `call` and > `apply` doesn't sit right with me. > > > Why should an arrow function be treated any differently than an explicitly > bound function (ie, via bind)? > > > > Hah, you beat me too it, I was typing in almost the exact same thing. And > not just bind, either - even the kind of workarounds people would use > before bind like 'var self = this' sorts of things. If someone writes code > using the arrow, what they want is to use the lexically scoped this - they > want to use 'this' just like any other reference captured by the closure. > > Any use of call or apply has to be done carefully and requires knowledge > of how 'this' is used. It effectively becomes another parameter to the > function. In cases of bind or an arrow function, 'this' is removed as a > parameter and is purely another captured reference. There's no special call > function to let you override other closed over values. Why should arrow > function's behavior for 'this' be any different? > > There is also no reason to think of => as all or nothing, jQuery and it's > APIs can still use function expressions where dynamic |this| is expected. > If a user tries to pass => to any of these APIs, they will learn quickly > that they've done it wrong. > > > However, there might be some utility (at least for debugging) in having a > Function.prototype.isThisBound method. It would return true for arrow > functions and functions created via Function.prototype.bind > This was actually expressed by the JSFixed group - that a means of detecting bound functions would essentially mitigate any perceived pain points of fat-arrow-functions. If we can get consensus on something like this, it would allay community concerns about the fat arrow. I would make one minor suggestion, and that is to shorten it to "isBound" Rick > > Allen > >
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