Find First and Last Position of Element in Sorted Array
<p>Given an array of integers <code>nums</code> sorted in non-decreasing order, find the starting and ending position of a given <code>target</code> value.</p>

<p>If <code>target</code> is not found in the array, return <code>[-1, -1]</code>.</p>

<p>You must&nbsp;write an algorithm with&nbsp;<code>O(log n)</code> runtime complexity.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> nums = [5,7,7,8,8,10], target = 8
<strong>Output:</strong> [3,4]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> nums = [5,7,7,8,8,10], target = 6
<strong>Output:</strong> [-1,-1]
</pre><p><strong class="example">Example 3:</strong></p>
<pre><strong>Input:</strong> nums = [], target = 0
<strong>Output:</strong> [-1,-1]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= nums.length &lt;= 10<sup>5</sup></code></li>
	<li><code>-10<sup>9</sup>&nbsp;&lt;= nums[i]&nbsp;&lt;= 10<sup>9</sup></code></li>
	<li><code>nums</code> is a non-decreasing array.</li>
	<li><code>-10<sup>9</sup>&nbsp;&lt;= target&nbsp;&lt;= 10<sup>9</sup></code></li>
</ul>
Array; Binary Search
function searchRange(nums: number[], target: number): number[] {
    const search = (x: number): number => {
        let [left, right] = [0, nums.length];
        while (left < right) {
            const mid = (left + right) >> 1;
            if (nums[mid] >= x) {
                right = mid;
            } else {
                left = mid + 1;
            }
        }
        return left;
    };
    const l = search(target);
    const r = search(target + 1);
    return l === r ? [-1, -1] : [l, r - 1];
}
