JavaScript Algorithms and Data Structures Projects - Caesars Cipher

JavaScript
1

Tell us what’s happening:
Describe your issue in detail here.

Why isn’t this working?!!!

Your code so far

function rot13(str) {
   let alphabet = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"]
   let arr = str.toUpperCase().split("")

   
   for(let letter = 0; letter < arr.length; letter++){
     if(alphabet.indexOf(arr[letter]) >= 0){
       arr[letter] = alphabet[letter + 13]
     }
   }

   return arr.join("")
}

console.log(rot13("a"));

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Challenge: JavaScript Algorithms and Data Structures Projects - Caesars Cipher

Link to the challenge:

2

Look at a more complete test case:

console.log(rot13("abcdefghijklmnopqrstuvwxyz"));