And on the principle, why is there a need for such `((MessageEvent) -> dynamic)?` signature, why ...

# javascript

[sdeleuze]

And on the principle, why is there a need for such ((MessageEvent) -> dynamic)? signature, why not just MessageEvent -> Unit?

[anton.bannykh]

Apparently the return value controls whether the event is cancelled or not: https://html.spec.whatwg.org/multipage/webappapis.html#eventhandler