Typescript + jQuery: correct way to use event state?

I have some simple popstate code for an SPA as follows:

module myModule {
    $(function () {
        $(window).on("popstate", function(e) {
            if (e.originalEvent.state !== null) {
                // code removed
            }
        });
    });
}

(The use of originalEvent is due to answers like this: popstate returns event.state is undefined)

This gives a compile error:

Property 'state' does not exist on type 'Event'.

e is a JQueryEventObject type and originalEvent is an Event type.

Now I've managed to work around the problem by defining this interface:

interface EventWithState extends Event {
    state: any;
}

(*I doubt "any" is really my best option here - if anyone knows what type state should be let me know, and more importantly how do I find that out for myself in such cases)

And I changed my above code like so:

module myModule {
    $(function () {
        $(window).on("popstate", function(e) {
            if ((<EventWithState>e.originalEvent).state !== null) {
                // code removed
            }
        });
    });
}

OK that works fine now and compiles to the original code I wanted. But it seems like an awkward workaround.

Is this the acceptable method to do this? Is something missing from typescript definitions? Or is there something I am missing.

Furthermore using e.state also doesn't work, however editing jquery.d.ts (from DefinitelyTyped) and adding state: any; to BaseJQueryEventObject fixes it in a similar way to my workaround. This is what makes me think something is missing from definitions for typescript regarding the Event state.

Thanks to Pilot for sharing the answer to another question, though it seemed unrelated at first, it did hold the clues and links for me to work out that I could cast to PopStateEvent rather than my own EventWithState.

module myModule {
    $(function () {
        $(window).on("popstate", function(e) {
            if ((<PopStateEvent>e.originalEvent).state !== null) {
                // code removed
            }
        });
    });
}

https://developer.mozilla.org/en-US/docs/Web/API/Event

https://developer.mozilla.org/en-US/docs/Web/API/PopStateEvent

And for the record, lib.d.ts does use "any" as the type for state:

interface PopStateEvent extends Event {
    state: any;
    initPopStateEvent(typeArg: string, canBubbleArg: boolean, cancelableArg: boolean, stateArg: any): void;
}

https://typescript.codeplex.com/SourceControl/latest#bin/lib.d.ts