### Problem

Given a sorted array of integers, find the starting and ending position of a given target value. Your algorithm's runtime complexity must be in the order of O(log n). If the target is not found in the array, return [-1, -1].

### Example

Given [5, 7, 7, 8, 8, 10] and target value 8, return [3, 4].

### JavaScript Code

```function searchRange(nums, target) {
if(nums == null || nums.length == 0){
return null;
}

var arr = [];
arr[0] = -1;
arr[1] = -1;

binarySearch(nums, 0, nums.length-1, target, arr);

return arr;
}

function binarySearch(nums, left, right, target, arr){
if(right<left)
return;

if(nums[left]==nums[right] && nums[left]==target){
arr[0]=left;
arr[1]=right;
return;
}

var mid = left+ parseInt((right-left)/2);

if(nums[mid]<target){
binarySearch(nums, mid+1, right, target, arr);
}else if(nums[mid]>target){
binarySearch(nums, left, mid-1, target, arr);
}else{
arr[0]=mid;
arr[1]=mid;

//handle duplicates - left
var t1 = mid;
while(t1 >left && nums[t1]==nums[t1-1]){
t1--;
arr[0]=t1;
}

//handle duplicates - right
var t2 = mid;
while(t2 < right&& nums[t2]==nums[t2+1]){
t2++;
arr[1]=t2;
}
return;
}
}

console.log(searchRange([2,2,2,3,4,4,8,8,8,9], 8));
```