Tail-Swap.js

/* You'll be given a list of two strings, and each will contain exactly one colon (":") in the middle (but not at beginning or end). The length of the strings, before and after the colon, are random.

Your job is to return a list of two strings (in the same order as the original list), but with the characters after each colon swapped.

Examples
["abc:123", "cde:456"]  -->  ["abc:456", "cde:123"]
["a:12345", "777:xyz"]  -->  ["a:xyz", "777:12345"]

*/

// solution

function tailSwap(arr) {
    const [aa, ab] = arr[0].split(":")
    const [ba, bb] = arr[1].split(":")
    return [`${aa}:${bb}`, `${ba}:${ab}`]
  }