Behavior of the "Encoder" module is unexpected - two call per notch

The fixed issue was that last was initialized with a 'valid' value that created invalid values. From a coding point of view though I'd preferred to leave the initializer in the constructor but choose a different initialization value, for example, -1, which results as well in correct behavior. Last but not least I'd left it there for clarity and follow the style of Espruino's goody over that standard JS to complain about not initialized values. - just 1-1/2 cents. ;-)