Yes, that is correct.
In case it wasn't obvious, event listeners are the typical use case where
you'd pass a reference to a member function somewhere else where a
reference needs to be saved in a variable. AS3 made this easy by
automatically binding member functions. JavaScript usually requires some
manual intervention to get event listeners to be called with the right
scope.
- Josh
On Sun, Jun 28, 2015 at 2:06 PM, Michael Schmalle <teotigraphix...@gmail.com
> wrote:
> So this only happens in javascript when you pass an object function to a
> variable? SO what I am saying is that not using this.func() is what looses
> the connection to the instance scope and then this becaomes window,
> correct?
>
> Mike
>
> On Sun, Jun 28, 2015 at 4:48 PM, Josh Tynjala <joshtynj...@gmail.com>
> wrote:
>
> > In Flash Player, when you save a reference to a member function, you can
> > call the function reference, and "this" will still be bound to the
> instance
> > where it came from.
> >
> > public class Test
> > {
> > public function Test()
> > {
> > this.func();
> > var func:Function = this.func;
> > func();
> > }
> >
> > private function func():void
> > {
> > trace(this); //in Flash, "this" will always be an instance of
> Test
> > }
> > }
> >
> > Basically, in the code above, the two calls to func() will behave the
> same
> > in Flash Player. However, in the current implementation of the
> transpiler,
> > that behavior is lost. When the reference to func() is called, "this"
> ends
> > up referring to the global window object instead.
> >
> > JavaScript function objects have a bind() function that let's you set
> what
> > "this" will refer to when the function is called:
> >
> >
> >
> https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind
> >
> > After modifying my code to use bind(), the two calls to func() will have
> > the same output:
> >
> > public function Test()
> > {
> > this["func"] = this.func.bind(this);
> > this.func();
> > var func:Function = this.func;
> > func();
> > }
> >
> > Would it be possible for the transpiler to automatically bind all member
> > functions to the correct scope to preserve the behavior that AS3
> developers
> > expect?
> >
> > - Josh
> >
>
