Add missing input binding method getType

[alandipert]

The reactR-generated Shiny input binding was missing an implementation for getType, which is required in order for shiny::registerInputHandler to work.

This PR adds an implementation that simply identifies the input by the unique name we're already collecting from the user.

[timelyportfolio]

@alandipert makes sense. I will likely wait a couple of weeks to avoid upsetting our friends at CRAN.

[timelyportfolio]

@alandipert just got to play with this and my rfabric examples. I am seeing

Listening on http://127.0.0.1:6004
Warning: Error in <Anonymous>: No handler registered for type checkbox:rfabric.faCheckbox
  [No stack trace available]
Error in (function (name, val, shinysession)  : 
  No handler registered for type checkbox:rfabric.faCheckbox

Will package authors need to change their code to work with this change? Or will the scaffold need to be changed?

I believe we are missing a registerInputHandler() on the R side that we will need to add in the scaffold on .onLoad. Does adding getType to the JavaScript require a handler on the R side?

[alandipert]

Hm, I didn't expect them to. I probably misunderstood what getType() is responsible for exactly 🤦‍♂ . I'll be able to look into this next week, and look forward to hearing whatever you discover.

[timelyportfolio]

@alandipert I mistakenly thought that getType() did not force require registerInputHandler(), but these Shiny lines seem to suggest that it does. In addition, the only registerInputHandler provided for official Shiny inputs also have a getType(). All the others don't specify getType so they use default getType which returns false.

As of now, I think we should revert this commit, but it does seem we need to find a way for a user to provide a getType() if necessary.

[timelyportfolio]

@alandipert these Shiny lines confirm that a handler is required if getType returns a : separated string.