I think the last sentence is really true. And yes, there are libraries that call back into user code, which makes them framework-like in this regards.
> A better definition might be that a framework imposes an entire 'application model' on you, and trying to step outside that predefined model is at your own risk
This is the kind of definition were 50% will call something a framework and the other half will call it a library then. Not sure if that is really helpful.
Yeah, if this is not just an once-off async callback (where you could just use a promise) but somthing more complicated, then this is indeed more framework-like and for me would be a reason to try to avoid it.
> A better definition might be that a framework imposes an entire 'application model' on you, and trying to step outside that predefined model is at your own risk
This is the kind of definition were 50% will call something a framework and the other half will call it a library then. Not sure if that is really helpful.