> 1) It's disallowed, Array instances can't have own accessor properties with > array index names. (and since Array.prototype is an Array instance it can't > either. An array instance could only inherit an accessor property with an > array index name from Object.prototype) > (snip) > > My preference is #1. Accessor properties are new to the standard and we get > to decide where they are and aren't allowed. ... (snip) > > > Opinions? >
Arrays already have a "magical" length property. may as well make indexes "magic" as well. As a user, I can't think of any particular use for making certain array indexes read only. > Here's another one. What happens if the length field is set [[Writable]]: > false and an attempt is subsequently make to define an array indexed > property (using either [[Put]] or Object.defineProperty) whose name is >= > than length? I suggest it fails (silently or not depending upon the Throw > parameter). I like this. It means you can make essentially fixed length arrays. Perhaps there is even room for implementation optimisation here if the user does this? > > What happens if the length is explicitly reduced such that an array indexed > property that is [[Configurable]]: false would be deleted by the ES3 array > [[Put]] algorithm? Alternatives: > > 1) The undeletable property is left undisturbed. (This > tosses out the ES3 invariant that length is > than the name of any array > indexed own properties. > > 2) The redefinition of length fails (silently or not > depending upon the Throw parameter). > > > > My preference is #1. #2 might be more consistent with my read-only length > recommendation but I'm concern that it requires implementations to use a two > pass algorithm to ensure atomicity. I'd prefer that not to impose that on > implementers. > > what if you had #1, but the length property, rather than being set to the new value, gets set to the index of the last undeletable property + 1. That's what I would expect to happen. _______________________________________________ Es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
