Flow-Router Extra Typescript types

[timsun28]

As discussed in issue there was an old request to add typescript types to this package.

This is a first start for implementing typescript types for Flow-Router extra. Basic setup from monti-apm routes types, but updated according to the docs from Flow-Router-Extra.

I still have a few small questions and a bug in the code itself that I wasn't able to figure out and could use the help from someone else with.

On the FlowRouter.current() documentation page, it is mentioned that the return value is an Object with 4 params, but there are more (as seen in the types file).

Later in the docs on the triggersEnter page, it is mentioned that the function has a property called: context {Route} that is equal to FlowRouter.current() function. But the FlowRouter.current() function has a context prop that it returns with different props. I think my implementation for the types is correct, but this might be a separate issue with the documentation that could be improved.

My issue is with the dynamic import (return type for waitOn function). type DynamicImport = Promise<typeof import(T)>; I have tried the following solution, but it's giving the error message at the last T: String literal expected.

[timsun28]

@dr-dimitru Thank you for merging this PR.

[Update] I've removed the local package from my project and update FlowRouter and it successfully found all the types!

[dr-dimitru]

@timsun28 I'm suggesting to start with a small file making sure types are pulled and recognized