Replace string with next character
JavaScript
var str = 'aaabbbcccdddeeefffggghhhiiijjjkklllmmoopppqqqrrrssstttuuuvvwwwxxxyyyzzzz';
var newStr = str.replace(/[a-z]/gi, function(char) {
return char === 'z' ? 'a' : String.fromCharCode(char.charCodeAt(0) + 1);
});
console.log(newStr);