feat: add types

[Eomm]

fixes #60

[Uzlopak]

This is confusing me. If you do "as RouteOptions" then it means that even invalid values are handled as valid. So you should remove the "as RouteOptions". If e.g. RouteOptions has options you dont use, e.g. handler use Omit utility type. e.g. Omit<RouteOptions, 'handler'>

[Eomm]

I checked a bit the ts docs and the Partial structure works best as Omit does not let the user to customize those parameters

[Uzlopak]

Last nitpick:
You use commas in your type definitions. I assume that semicolons are the preferred way and i personally also prefer semicolons.

The typescript documentation uses semicolons everywhere and also a google search says that:
https://www.google.com/search?q=typescript+type+comma+or+semicolon&oq=typescript+types+comma+o&aqs=chrome.1.69i57j0i22i30.7144j0j4&client=ms-android-samsung-gj-rev1&sourceid=chrome-mobile&ie=UTF-8

But that is something you can decide.