Count Primes LeetCode solution in JavaScript

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function makeSieve(n) {
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  let arr = new Array(n + 1);
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  arr[0] = false;
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  arr[1] = false;
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  arr.fill(true, 2, arr.length);
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  for (let i = 2; i * i < n; i++) {
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    if (arr[i] === true) {
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      for (let j = i * i; j <= n; j += i) {
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        arr[j] = false;
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      }
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    }
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  }
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  let count = 0;
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  for (let i = 0; i < n; i++) {
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    if (arr[i] == true) {
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      count++;
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    }
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  }
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  return count;
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}
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var countPrimes = function (n) {
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  let numberOfPrimes = makeSieve(n);
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  return numberOfPrimes;
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};