Maximum Difference Between Node and Ancestor LeetCode solution in JavaScript

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var maxAncestorDiff = function (root) {
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  let ans = 0;
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  const traverse = (r = root, mx = root.val, mn = root.val) => {
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    if (!r) return;
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    ans = Math.max(ans, Math.abs(mx - r.val), Math.abs(mn - r.val));
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    mx = Math.max(mx, r.val);
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    mn = Math.min(mn, r.val);
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    traverse(r.left, mx, mn);
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    traverse(r.right, mx, mn);
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  };
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  traverse();
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  return ans;
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};