Solution attempt (without bruteforcing) to the infamous problem 4 from https://blog.svpino.com/2015/05/07/five-programming-problems-every-software-engineer-should-be-able-to-solve-in-less-than-1-hour

fiveprobs.js

function maximizer(list){

    function sortIt(x, y){
        x += '';
        y += '';
        if(x === y){
            return 0;
        }
        if(x.length === y.length){
            if(x < y){
                return 1;
            }
            if(x > y){
                return -1;
            }
        }
        if(x.length < y.length){
            var a = x,
                b = y.slice(0, x.length),
                c = y.slice(x.length),
                test = sortIt(a, b);
            
            if(test !== 0){
                return test;
            } else {
                return sortIt(b+c, c+a);
            }
        }
        if(x.length > y.length){
            var a = x.slice(0, y.length),
                b = x.slice(y.length),
                c = y,
                test = sortIt(a, c);
            
            if(test !== 0){
                return test;
            } else {
                return sortIt(b+c, a+b);
            }
        }
    }
    return list.sort(sortIt).join('')/1;
}