@Jeremy: something similar could be achieved with a private name (I want object properties) and accessor properties, but it lacks the advantages that I mentioned (also outside classes and object literals, the accessor properties are ugly). @Claude: that's not easy to use, and also it can be done outside the execution context.
On Fri, Dec 13, 2013 at 6:20 PM, Claude Pache <[email protected]>wrote: > > If you are not paranoid, you can just use nonwritable properties. That > forces you to use `Object.defineProperty` to change the value, so you are > protected against accidental assignments. > > function Obj() { > Object.defineProperty(this, 'x', { value: 2, writable: false, > enumerable: true, configurable: true }) > this.setX = function (val) { > Object.defineProperty(this, 'x', { value: val }) > } > } > > o = new Obj > o.x = 17 // assignment will fail; moreover, in strict mode, an error > is thrown > o.x // 2 > o.setX(18) > o.x // 18 > > It doesn't prevent the user from hanging themself with > `Object.defineProperty(o, 'x', { value: 17 })`; but at least, it won't be > by chance! > > —Claude > > > Le 13 déc. 2013 à 14:34, raul mihaila <[email protected]> a écrit : > > Hello, was there any proposal for object properties that can be read from > anywhere but are writable only from the execution context where the name > associated with the property was defined? Something like: > > function Obj() { > ro x; // read only name x > this.x = 2; > this.setX = function (val) { > this.x = val; > }; > } > > var o = new Obj; > > o.x; // 2 > o.x = 43; // throws some error > o.x; // 2 > o.setX(100); > o.x; // 100 > > The advantages would be that you are sure that there are no side effects > when the property is accessed and also I'm guessing you have no function > call overhead. > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > >
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