Number of Sub-arrays With Odd Sum LeetCode solution in JavaScript

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var numOfSubarrays = function (arr) {
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  let mod = 1e9 + 7,
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    sum = 0,
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    odds = 0,
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    evens = 0;
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  //Notice that I do not need to keep track of the prefixSums, I just need the total count of odd and even PrefixSums
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  for (let i = 0; i < arr.length; i++) {
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    sum += arr[i];
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    odds += Number(sum % 2 == 1);
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    evens += Number(sum % 2 == 0);
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  }
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  return (odds * evens + odds) % mod;
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};