Anti Caps

Write a function called antiCaps, which accepts a string and manipulates it as follows.

• Uppercase characters will become lowercase.
• Lowercase characters will become uppercase.

antiCaps('Hello')  // hELLO
antiCaps('racEcar')  // RACeCAR
antiCaps('bAnAnA')  // BaNaNa

Hint

Here is a helper function that will return true if the letter is uppercase, and false if the letter is lowercase:

function isCaps(letter) {
  return letter === letter.toUpperCase();
}

Extra credit

• Have the function return double letters if originally uppercase
• Have the function return the letter and a symbol if originally lowercase.