I'd go for as short (but still readable) as possible.

  > robot.keys("Type a string")

  > robot.keys(ENTER)   // ENTER is an integer key value

(I've been thinking about this while trying to make an idiomatic node client for Selenium WebDriver... https://github.com/hugs/34#api)

Importing enum values into global/function/module local namespace has always been a PITA for javascript environments. Any suggestion on how to do this cleanly?

I'm sure it's possible, but one way to avoid it -- turn the constant into a method:

  > robot.keys.ENTER()

(Not great for key combos, though...)

I'd then go with

  robot.keys.enter()

(since enter is a function, not a constant) and make it chainable by returning `robot.keys`.

  robot.keys.ctrl().enter()

You'd probably want something slightly different than keys - at least some way to different between key presses and hold the keys down at the same time.