Alphabet next letter in js

by Khadeer Mohammed

JavaScript

function wordconvert(str, type) {
	var str2 = '';
  for( var k=0;k<str.length;k++) {
      var l = str[k];
      if(l === "z" || l === "_" || l === '-'){
      	l = '-';
      }
      str2 += String.fromCharCode(l.charCodeAt(l.length - 1) + type)
  }
	console.log(str2);
}

wordconvert("khadeer", + 1);
wordconvert("libeffs", - 1);