Kata: Reverse words

Write a reverseWords function that accepts a string a parameter, and reverses each word in the string. Every space should stay, so you cannot use words from Prelude.

const reverseWords = str => {
  return str
    .split(' ')
    .map( word => word.split('').reverse().join('') )
    .join(' ');
}

reverseWords("This is an example!"); // "sihT si na !elpmaxe"

Test:

Test.assertEquals(reverseWords("This is an example!"), "sihT si na !elpmaxe")