Trouble when extending any JS extern

[oleg karasev]

I got "Uncaught TypeError: Cannot read property 'prototype' of undefined " when extending any JS-written class.

For testing purposes i try to extend jquery class in new project:

class Main extends JQuery{

static function main()  {}

}

it compiles OK, but after run it causes error.

this was only example. The main goal is to extend custom js library in my haxe project.

[Juraj Kirchheim]

That because at that point in time js.JQuery is undefined. That's
because it gets defined here:
https://github.com/HaxeFoundation/haxe/blob/development/std/js/JQuery.hx#L396

And __init__ functions are run *after* all class definitions are booted.

You should not extend JQuery. Use plain old composition or `abstract`
or `using` and you'll be fine.

Regards,
Juraj

[oleg karasev]

I am new in haxe. Can you explain what is the "plain old composition"? 

The JQuery was only for example. I need to extend my custom JS class in my project.

For example: 

extern class my_custom_js_class{

 method1.....

 method2.....

 method3.....

}

how to extend it in my haxe project?

воскресенье, 15 сентября 2013 г., 16:06:59 UTC+4 пользователь back2dos написал:

[oleg karasev]

i had tested this solutions and all of them are unsuitable

1) "using" and "abstract" classes cannot be extended, but there are some of "childs" in my project:

class child1 extends my_extern_js_class

class child2 extends child1

class child 3 extends child2

2) composition.... hmmm.. wrappers? Bad solution.

Is there any "fine" way to init JS *before* extending?

[oleg karasev]

I found it!!! Thanks very very!!!!

in "__init__" of my external was compiler directive to include my_extern_js_class.JS 

I removed that include. Then i included my_extern_js_class.JS  manually from .html *before* project .js file.

Now it works!

Your answer about __init__ was very helpfull, thanks a lot. And excuse for my bad english :)

[Juraj Kirchheim]

On Sun, Sep 15, 2013 at 4:14 PM, oleg karasev <okar...@gmail.com> wrote:
> i had tested this solutions and all of them are unsuitable
> 1) "using" and "abstract" classes cannot be extended, but there are some of
> "childs" in my project:
>
> class child1 extends my_extern_js_class
> class child2 extends child1
> class child 3 extends child2

What I mean is something like this:

extern class Foo { ... }

class FooMagic {
static public function superFoo(foo:Foo, x, y, z) { ... }
}

using FooMagic;

var f:Foo = ...;
f.superFoo(1, 2, 3);

> 2) composition.... hmmm.. wrappers? Bad solution.

More often than not, it's the best solution. But let's not get started on that.

As long as things are working for you, all is well :)

Regards,
Juraj