Continuous Subarray Sum LeetCode solution in JavaScript

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var checkSubarraySum = function (nums, k) {
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  const n = nums.length;
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  if (n < 2) {
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    return false;
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  }
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  const map = new Map();
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  // edge case - to handle sum % k === 0 and
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  // if the first element of array is a multiple of k, condition 0 - (-1) = 1 > 1 wil fail (min length of subarray must be 2)
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  map.set(0, -1);
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  let sum = 0;
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  for (let i = 0; i < n; ++i) {
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    sum += nums[i];
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    sum = sum % k;
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    // handles min length of subarray must be 2
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    if (map.has(sum) && i - map.get(sum) > 1) {
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      return true;
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    } else if (!map.has(sum)) {
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      map.set(sum, i);
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    }
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  }
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  return false;
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};