Object.equals() and Object.clone()

Kevin Barabash kevinb at khanacademy.org
Tue Nov 15 04:51:02 UTC 2016


I didn't know about structured clone so I looked it up.  It looks pretty
promising.  As for checking if two things are equal, maybe it makes sense
for objects to define their own `.equals(other)` methods.

https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm

On Mon, Nov 14, 2016 at 9:31 PM, Eric Devine <devineej at gmail.com> wrote:

> How about beginning with the HTML structured clone algorithm, and a
> `Symbol.clone` property to allow an object to optionally define it's own
> cloning behavior?
>
> On Mon, Nov 14, 2016 at 9:02 PM, Isiah Meadows <isiahmeadows at gmail.com>
> wrote:
>
>> I agree. Also, consider iterables. Should their `Symbol.iterator` method
>> be called? There's no obvious behavior for the details, and people's
>> opinions differ on what should be correct.
>>
>> On Mon, Nov 14, 2016, 20:58 Frankie Bagnardi <f.bagnardi at gmail.com>
>> wrote:
>>
>> It's pretty hard to decide how these behave, specifically with custom
>> classes. Focusing on Object.clone...
>>
>> - with classes do you call the constructor, and with what arguments?
>> - HTMLElement and sub classes can't be constructed directly, what happens
>> with them?
>> - do you copy internal properties? this would make it hard to polyfill
>> - how does it behave with getters and setters?
>> - with regular expressions do you copy the lastIndex?
>>
>> Most of those apply to Object.equals also.
>>
>>
>>
>> On Mon, Nov 14, 2016 at 6:25 PM, Kevin Barabash <kevinb at khanacademy.org>
>> wrote:
>>
>> It would be nice if deep equality checking and deep cloning of objects
>> was included in the standard library.  Has there been any proposals around
>> including these in the past?
>>
>> – Kevin
>>
>>
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