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. 
**/

function count(x) {
  var numbers = [];
  if (x % 2 === 0) { // check that x is even
    for (var i = 0; i < x; i += 2) { // assign i to 0; give i the limit of x; and increment by 2
      numbers.push(i);
    }
  } else {
    for (var j = 1; j < x; j += 2) { // assign i to 1; give i the limit of x; and increment by 2
      numbers.push(j);
    }
  }
  return numbers;
}

/* ES6 */
const count = x => {
  if (x % 2 === 0) {
    

Ta ai a versão funcional

const showEvens = ( num ) => 
  Array.from(  { length: num }, ( k, v ) => { if ( !(v % 2) ) return v } )
       .filter( num => num !== undefined )

const showOdds = ( num ) => 
  Array.from( { length: num }, ( k, v ) => { if ( v % 2 ) return v } )
       .filter( num => num !== undefined )


const magic = ( num ) => !( num % 2 ) ? showEvens( num ) : showOdds( num )

const myNumbahs11 = magic(11)
const myNumbahs12 = magic(12)
console.log(`myNumbahs11: `, myNumbahs11)
console.log(`myNumbahs12: `, myNumbahs12)

Pensei em algo assim
https://gist.github.com/anabastos/db389fbd9c3d830fd550ca21fb07271e

const notUndefined = num => num !== undefined
const isOdd = num => ((num % 2) === 0)
const isEven = num => !isOdd(num)
const numberTest = (cp, num) => (cp(num) ? num : undefined)
const makeTest = cp => (k, v) => numberTest(cp, v)

const makeArrBuilder = cp => num =>
  Array.from({ length: num }, makeTest(cp)).filter(notUndefined)

const showEvens = makeArrBuilder(isEven)
const showOdds = makeArrBuilder(isOdd)

const magic = (num) => (isEven(num) ? showEvens(num) : showOdds(num))

const myNumbahs11 = magic(11)
const myNumbahs12 = magic(12)
console.log(`myNumbahs11: `, myNumbahs11)
console.log(`myNumbahs12: `, myNumbahs12)

uma evolução da versão do @suissa

https://gist.github.com/lubien/ba700ca513af78ab55f408b5aa40c4fa

Nice, @lubien. Ａｅｓｔｈｅｔｉｃｓ. Por um pouco nem parece JavaScript.

Em Common Lisp:

(defun counting (n)
  (loop with f = (if (evenp n) #'evenp #'oddp)
        for x from 0 to below
        when (funcall f x)
          collect x))
(counting 10) ;; (0 2 4 6 8)
(counting 11) ;; (1 3 5 7 9)

const count = x => [...Array(x).keys()].filter(y => !((x + y) % 2));

function show_odd_even(number) {
  var numbers = [];
  for (var cont = verify_odd_even(number); cont < number; cont+=2) {
    numbers.push(cont);
  }
  return numbers;
}

function verify_odd_even(number) {
  if (number % 2 === 0) {
    return 0;
  }
  return 1;
}

who needs readability anyway

const show = n => [...Array(Math.ceil(n / 2) - n % 2).keys()].map(x => x * 2 + n % 2);

also, OP's comment in line 16 is wrong.

uhuhuhuuhhuhuhuhuhuhuhuhuhhuhuh funcional com Kotlin
val numbersPairsOdds = arrayOf(1, 3, 5, 6)
fun calc(x: Array<Int> = numbersPairsOdds) = x.map { if (it % 2 == 0) { print("número par -> $x , ") } else { print("número impar -> $x ") } }