Type annotation with flow syntax and defaulting of args is breaking React Class validator

Hello,

Thanks for your library!

I ran into an issue where a option (flow annotation) argument in a handler was causing my class to not be parsed.. resulting in You have to export at least one valid React Class!. Defaulting the arg also seems to break things.

Breaks:

handleThings = (id: number, active?: boolean) => () => {
   things..
}

handleThings = (id: number, active: boolean = false) => () => {
   things..
}

Works:

handleThings = (id: number, active: boolean) => () => {
   things..
}

Thanks!

Start at the React Class validator and reproduce the two failing JSX examples alongside the working example. Trace why optional Flow annotations and default argument values prevent the class from being recognized; done means all three forms are parsed as valid React classes.