Split string into an array by specified lengths of characters and pad each element with a specified character. Given a value ```str = 'abcdefg``` Running this function ```splitBy str, 2, '-'``` should produce an array ```['ab', 'cd', 'ef', 'g-']```

splitBy.coffee

# str: The string we wish to split up
# length: how many characters of 'str' should each array element contain
# padWith: what to padd the last element with
splitBy = (str, length, padWith) ->
  pad = (str) ->
    str = "#{str}#{padWith}" for i in [str.length...length]
    str    
  pad (str.slice i, i+length), length, padWith for i in [0...str.length] by length
    

str = 'abcdefgdlkhjatbhjsdfhjkadskjh'

console.log splitBy str, 4, '_'