const str = "JavaScript is Awesome!";

const result = str
  .split(" ")
  .map((word, i) => 
    i % 2 === 0
      ? word.toUpperCase()
      : word.toLowerCase()
  )
  .join("-");

const reversed = result
  .split("")
  .reduce((acc, char) => char + acc, "");

console.log(reversed);