Non-decreasing Array LeetCode solution in JavaScript

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var checkPossibility = function (nums) {
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  let changed = false;
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  for (let i = nums.length - 1; i > 0; i--) {
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    if (nums[i - 1] > nums[i]) {
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      if (changed) return false;
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      if (i === nums.length - 1 || nums[i - 1] < nums[i + 1])
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        nums[i] = nums[i - 1];
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      else nums[i - 1] = nums[i];
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      changed = true;
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    }
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  }
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  return true;
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};