Asterisk it.js

/*
You are given a function that must insert an asterisk between every pair of even digits in an integer n, that should be converted to a string(toString), received as parameter and return it.

n can be a string/an array containing integers only.

If n is an array, put the elements together then put the asterisk, treating them as a string. e.g. [1, 2, 4, 8, 16] ==> "12*4*816"

Here we will consider all the numbers that n % 2 == 0 as even numbers.

Have fun!
*/
function asteriscIt(n) { 
  if (Array.isArray(n)) return n.join('').split('').map((v,i,arr)=>v%2===0&&arr[i+1]%2===0?v+'*':v).join(``)
  return (''+n).split('').map((v,i,arr)=>v%2===0&&arr[i+1]%2===0?v+'*':v).join(``)
};