From: Axel Rauschmayer [mailto:[email protected]] Sent: Friday, March 16, 2012 18:35 To: Domenic Denicola Cc: Russell Leggett; Kevin Smith; es-discuss Subject: Re: Using Object Literals as Classes
Just to contribute to this... er... fun-thread... My team uses the closure pattern for our "classes" (i.e. no prototype methods at all), since we value encapsulation. I can't imagine we're alone. Do you see privacy via closures and prototypes as mutually exclusive? In my experience, they work well in combination. Do you add all of your methods to the instance? That would have the advantage of making it easier to access private data from public methods, but would consume more memory. In theory I see them as complementary, but in practice I have never been able to integrate prototypes. Consider: a method can only be attached to a prototype if it needs access to an instance’s public state only, and not to its private state. These cases are extremely rare. And when they do occur, I usually ask myself—is this really an instance-level method? Why not make it a module-level method that operates on instances of my class? We have so far made the trade-off of sacrificing memory for encapsulation. (Although, I still find it strange that modern JITers don’t pull out of the code of the method to reuse in each instance, and instead duplicate it every time. Cf. the “Joining” section of [1].) It hasn’t bitten us yet. [1]: http://wiki.ecmascript.org/doku.php?id=strawman:const_functions So any class solution that doesn't fully incorporate private names (e.g. by making them awkward via manual Name.create(), etc.) will leave that audience behind, still using closures and ignoring any new class sugar. True. Something along the lines of: class C { private { age, strength } /* syntactic sugar for module name from "@name"; var age = name.create(); var strength = name.create(); */ // private method @incAge() { this.@age<mailto:this.@age>++; } } This does look familiar, and quite useful. But it’s certainly outside the scope of “object literals as classes,” which I think ties to my original point in supporting the OP that object literals alone are not sufficient.
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