Here is a code snippet:
----
var p = {};
(function(){
var a;
Object.defineProperty(p, 'a', {get:function(){return a;},
set:function(v){a = v;}});
})();
var o1 = Object.create(p); var o2 = Object.create(p); o1.a = 1; console.log(o1.a, o2.a); // 1 1 o2.a = 37; console.log(o1.a, o2.a); // 37 37 ----'a' is an own property neither of o1 nor o2. (Firefox may say the opposite, but I've been told, it's fixed and going to be released on FF 6 or 7 [1] [2]). a "value" (so to say) is shared among the instances.
David [1] https://bugzilla.mozilla.org/show_bug.cgi?id=636989 [2] https://bugzilla.mozilla.org/show_bug.cgi?id=637994 Le 23/06/2011 13:19, David Bruant a écrit :
Hi,In a the provided example, you assign a value. Can't you just use a getter/setter pair on the prototype chain? It sounds like it would solve your use case (without the syntax sugar). On ES5 - 8.12.5 step 4 & 5, the prototype chain is climbed to look up for an accessor and if there is a setter (anywhere on the prototype chain), this setter is called. Combined with the fact that a getter naturally do the same thing for getters, you have your way to change a value "directly on the prototype chain". Of course, if you want to change the property descriptor on the prototype chain, none of what I said apply.David Le 21/06/2011 17:24, Axel Rauschmayer a écrit :As a loose analog to the prototype-chain-traversing getPropertyDescriptor(), I would still like to have something that allows one to easily *change* properties higher up the prototype chain (e.g. to use a prototype to share state).Maybe it would be enough to just have Object.getDefiningObject(obj, propName):http://www.mail-archive.com/[email protected]/msg06652.html But I can also imagine syntactic sugar: obj.foo := "abc" desugars to Object.getDefiningObject(obj, "foo").foo = "abc"_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
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