SOLUTION: Caesars Cipher - freeCodeCamp (JavaScript Algorithms and Data Structures)

 Caesars Cipher

One of the simplest and most widely known ciphers is a Caesar cipher, also known as a shift cipher. In a shift cipher the meanings of the letters are shifted by some set amount.

A common modern use is the ROT13 cipher, where the values of the letters are shifted by 13 places. Thus A ↔ N, B ↔ O and so on.

Write a function which takes a ROT13 encoded string as input and returns a decoded string.

All letters will be uppercase. Do not transform any non-alphabetic character (i.e. spaces, punctuation), but do pass them on.

SOLUTION: 

function rot13(str) {   return str.split("").map(item => {     let a = item.replace(/[A-Z]/g,(item.charCodeAt(0) + 13) > 90 ? String.fromCharCode(item.charCodeAt(0) + 13 - 90 + 64): String.fromCharCode(item.charCodeAt(0) + 13))     return a   }).join(""); } rot13("SERR PBQR PNZC"); console.log(rot13("SERR PBQR PNZC"));

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