getOwnPropertyDescriptor side effects

Adam Klein adamk at chromium.org
Fri Jan 6 19:22:03 UTC 2017


With the advent of Proxy in ES2015, getOwnPropertyDescriptor can always
have side-effects:

Object.getOwnPropertyDescriptor(new Proxy({}, { getOwnPropertyDescriptor()
{ throw "hello world" } }), "foo")

On Fri, Jan 6, 2017 at 11:11 AM, Francisco Tolmasky <tolmasky at gmail.com>
wrote:

> Is there any position on whether getOwnPropertyDescriptor should not have
> side-effects? I ask because some v8 getOwnPropertyDescriptor *do* have side
> effects (for example, Object.getOwnPropertyDescriptor(new Error, “stack”)
> will call Error.prepareStackTrace (it used to not)). Currently I
> treat getOwnPropertyDescriptor as a “safe” way to observe an object —
> (unlike say calling each member on an object which could set off getters).
>
> --
> Francisco Tolmasky
> www.tolmasky.com
> tolmasky at gmail.com
>
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