Show Me the Evens - Show me the Odds

show-me.js

/**
* Show Me the Evens - Show me the Odds 
* Diana is learning to count and she just learned the difference between odds and even numbers. 
* She wants to have some fun, so she picks a random number. 
* If that number is even, she decides to count all the even numbers up to it starting from 0 up to (but not including) the input. 
* If not, she decides to count all the odd numbers up to that number starting from 1 (but not including) the input. 
**/

const
  range = x => y =>
    Array.from({length: (y - x)})
      .map((_, i) => i + x)

, filter = f => xs =>
    xs.filter(f)

, even = x =>
    (x % 2) === 0
    
, odd = x =>
    !even(x)
  
  // Inspired by: https://gist.github.com/anabastos/db389fbd9c3d830fd550ca21fb07271e
, showMe = x =>
    filter(even(x) ? even : odd)(range(0)(x))
  
showMe(10)