Find the Kth Largest Integer in the Array LeetCode solution in JavaScript

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var kthLargestNumber = function (nums, k) {
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  const n = nums.length;
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  k = n - k;
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  return quickSelect(nums, k, 0, n - 1);
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  function quickSelect(arr, selectIdx, left, right) {
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    const pivotIdx = Math.floor(Math.random() * (right - left + 1) + left);
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    const pivotNum = arr[pivotIdx];
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    swap(arr, pivotIdx, right);
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    let swapIdx = left;
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    for (let i = left; i < right; i++) {
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      if (compare(arr[i], pivotNum) < 0) {
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        swap(arr, swapIdx, i);
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        swapIdx++;
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      }
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    }
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    swap(arr, swapIdx, right);
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    if (swapIdx === selectIdx) return arr[selectIdx];
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    if (swapIdx > selectIdx)
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      return quickSelect(arr, selectIdx, left, swapIdx - 1);
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    if (swapIdx < selectIdx)
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      return quickSelect(arr, selectIdx, swapIdx + 1, right);
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  }
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  function compare(numStr1, numStr2) {
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    if (numStr1.length > numStr2.length) return 1;
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    if (numStr2.length > numStr1.length) return -1;
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    return numStr1.localeCompare(numStr2);
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  }
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  function swap(arr, i, j) {
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    [arr[i], arr[j]] = [arr[j], arr[i]];
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  }
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};