hi Bilai, there’s no reliable way to deep-copy arbitrary js-objects. the most
practical “general” solution is two-step:
1. deep-copy JSON-data first, e.g. ```var bb = JSON.parse(JSON.stringify(aa))```
2. custom-copy non-JSON-data in a second-pass, e.g. ```bb.innerObj.func =
aa.innerObj.func```
like this real-world example [1]:
```javascript
local.jsonCopy = function (obj) {
/*
* this function will [JSON] deep-copy obj
*/
return obj === undefined
? undefined
: JSON.parse(JSON.stringify(obj));
};
...
// update apiDict
self = local.apiDict[key.join('.')] = local.apiDict[self._methodPath] =
local.jsonCopy(self); // step 1 - deep-copy JSON-data first
// init ajax
self.ajax = function (swaggerJson, onError) { // step 2 - custom-copy/add
non-JSON-data in second-pass
return local.apiAjax(self, swaggerJson, onError);
};
```
[1] deep-copy swagger client-object with functions
https://github.com/kaizhu256/node-swgg/blob/2018.9.8/lib.swgg.js#L2181
kai zhu
[email protected]
> On 23 Oct 2018, at 10:25 PM, Naveen Chawla <[email protected]> wrote:
>
> Correction, suppose const b = { a : b } . Circular references can be cloned
> trivially, as far as I can tell
>
> On Tue, 23 Oct 2018 at 20:52 Naveen Chawla <[email protected]
> <mailto:[email protected]>> wrote:
> Is there any real problem with circular reference cloning? I don't see any,
> Please let me know in the simplest case e.g. { a: a } (obviously contrived
> syntax here)
>
> Otherwise, I agree completely about the 4 dots being the wrong syntax for
> this, precisely for the reason you gave
>
> On Tue, 23 Oct 2018 at 18:18 Henrique Barcelos <[email protected]
> <mailto:[email protected]>> wrote:
> IMO, this would be very problematic.
>
> 1. 4 dots are visually almost identical to 3 dots. This could introduce
> severe bugs because of a simple hard to spot typo.
>
> 2. Deep traversing will always have performance problems in some cases.
> Dealing with circular references can take this issue even further.
>
> I believe such functionality should be used in very specific situations,
> where object shape is well-known, not very deep and definitely not circular.
> So, supporting this at the core of the language will probably be frowned upon
> by the community.
>
> Em ter, 23 de out de 2018 08:57, Ahad Cove <[email protected]
> <mailto:[email protected]>> escreveu:
> Hello Scripters,
>
> I really appreciate everything you all have done for the language and have no
> complaints over here.
> I do have a suggestion though :)
>
> At work we’ve almost got rid of lodash, except we still need it for DeepCopy
> vs rolling our own.
> It’s the same with my side projects. I don’t use lodash because the main
> times that I need deep copy is when I’m either digging into the Redux store
> using React, or copying an observable in the Angular world.
>
> I believe ES Script users would appreciate having a deep copy spread operator
> tremendously.
>
> My proposal is to go off of the current spread operator we currently have in
> ES and make it 4 dots for a deep spread. This can be used on Objects or
> Arrays.
>
> ‘’’js
> const oldDeepObj = {
> InnerObj: {
> func: () => return ‘wow’
> }
> }
>
> const obj = {....oldDeepObj}
> obj.innerObj.func = () => return ‘nice’
>
> oldDeepObj.innerObj.func()
> > wow
> ‘’’
>
> Thank you!
> Looking forward to hearing back from you all.
> If there’s any other questions let me know
>
> - Bilal Abdullah
> _______________________________________________
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> --
> Henrique
>
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