constructor, super, and data members issue

[Aaron Gray]

Yeah it does look like its badly "broken by design".

On Fri, 24 Aug 2018 at 22:13, Jordan Harband <ljharb at gmail.com> wrote:

> I'm afraid that still wouldn't solve the problem; the superclass's code is
> all 100% completed before the subclass has `this` available.
>
> On Fri, Aug 24, 2018 at 1:52 PM, Ranando King <kingmph at gmail.com> wrote:
>
>> Aaron, congratulations! You just tripped over a new reason for me to
>> revive issue #123. The only way to get that to work is to have the default
>> values on the prototype. The problem comes because `this` doesn't even have
>> a value until the last call to `super()` returns. If a `class` doesn't have
>> a base `class` it essentially has Object as a base `class` and `super` is
>> implicitly called. So unless the default public field values are on the
>> prototype, there's literally no way to have them initialized before the
>> base classes are initialized.
>>
>> On Fri, Aug 24, 2018 at 3:15 PM Aaron Gray <aaronngray.lists at gmail.com>
>> wrote:
>>
>>> I am having an issue with order semantics regarding
>>> https://github.com/tc39/proposal-class-fields with derived classes
>>> defining or overriding data member values that are used in the base class
>>> constructor for initialization of properties of the class.
>>>
>>> This means the Super Class / Base Class'es constructor does not yet have
>>> access to the default field values of the derived class it is initiating.
>>>
>>>     class Base {
>>>         constructor() {
>>>              ....
>>>              .. idAttribute ..
>>>              ....
>>>         }
>>>         idAttribute = 'id';
>>>     }
>>>    class Derived extends Base {
>>>         constructor() {
>>>              super();
>>>              ....
>>>         }
>>>         idAttribute = '_id';
>>>    }
>>>
>>> All would mean having a separate initialize() function, but even this
>>> solution is flawed when there is a third level in the hierarchy. And as
>>> super() is required it means there seems to be no way round this issue. The
>>> only way I can see is some form of override keyword ?
>>>
>>>
>>> Has anyone got any solutions to this issue or work arounds ?
>>> --
>>> Aaron Gray
>>>
>>> Independent Open Source Software Engineer, Computer Language Researcher,
>>> Information Theorist, and amateur computer scientist.
>>> _______________________________________________
>>> es-discuss mailing list
>>> es-discuss at mozilla.org
>>> https://mail.mozilla.org/listinfo/es-discuss
>>>
>>
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>>
>>
>

-- 
Aaron Gray

Independent Open Source Software Engineer, Computer Language Researcher,
Information Theorist, and amateur computer scientist.
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