frequency iterativo

function frequency(array_elements) {

    array_elements.sort();
    var current = null;
    var cnt = 0;
	var result = [];
    for (var i = 0; i < array_elements.length; i++) {
        if (array_elements[i] != current) {
            if (cnt > 0) {
                result.push([current, cnt]);
            }
            current = array_elements[i];
            cnt = 1;
        } else {
            cnt++;
        }
    }
  
  	if(cnt > 0 )
    {
        result.push([current, cnt]);
    }
    return result;
}