It depends on what kind of `extends` you mean: - Inheritance: Even though data being kept in prototypes is rare, it’s usually better to chain prototypes even when ignoring aliasing problems (no redundant properties, instanceof works transitively). Performance degradation should be negligible due to internal optimizations.
- Merging objects: Shallow copy is the way to go. On Nov 13, 2011, at 11:08 , Jake Verbaten wrote: > > > Neither of them are fit for standardization. Selfish and Prototype are both > incapable of correctly "deep copying" arrays or objects, > > Why does it matter that they don't deep copy? Deep copying is a difficult > problem that needs to be standardized separately. I've personally avoided > deep copying for this reason and don't use it anymore. > > One can accept that an extend is merely a shallow copy properties by > reference, because this (although limited) behavior is easy to understand. > > I have a version of Object.extend that is a "shallow own merge". > > However having a deep copy mechanism that works without obscure edge-cases > would be great. Of course it would be nice if we had the choice of deep vs > shallow copy within the API. > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss -- Dr. Axel Rauschmayer a...@rauschma.de home: rauschma.de twitter: twitter.com/rauschma blog: 2ality.com
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