compress string

compression

var compress = function(str){
    var compressed = "";
    var previous = "";
    var count = 1;
    var last = str.length - 1;
    
    sorted = str.split('').sort();

    sorted.forEach(function(letter,i) {

        if (i === 0){
            previous = letter;
            
        } else if (previous === letter && i !== last) {
            console.log('next',letter)
            count += 1;
            
        } else if (i === last){
            if (letter !== previous){
              compressed += previous + count;
              compressed += letter + 1;
    
            } else {

            count += 1;
            compressed += letter + count
            
            }
        
        } else {

            compressed += previous + count;
            count = 1;
            previous = letter;
        }

    })

    return compressed.length > str.length ? str : compressed;
}

var str = "ababc"
console.log(compress(str))