insertionSort

var insertionSort = (arr) => {
    arr = arr.slice();

    for(var i = 1; i < arr.length; i++){
        var current = arr[i];
        var j = i - 1;
        while(j >= 0 && arr[j] > current){
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = current;
    }
    return arr;
}

insertionSort([5,4,3,2,1]) //[1,2,3,4,5]