Sieve of Eratosthenes: Find Prime numbers in a given range

const sieveOfEratosthenes = n => { // initially label every number from [0, n] as a prime number const primeNumbersSieve = new Array(n + 1).fill(true); // since 0 and 1 are not prime numbers, label them as false primeNumbersSieve[0] = primeNumbersSieve[1] = false; /** * we stop the loop when i > sqrt(n) which is equivalent * to i * i <= n. this is because the maximum divisor of n * is sqrt(n), therefore if we allow values of i > sqrt(n) * in the loop, we will end up with a value for i where i * i > n */ for (let i = 2; i * i <= n; i++) { if (primeNumbersSieve[i]) { /** * skip all multiples of i < i * i because they have * already been checked */ let k = i * i; while (k <= n) { // remove all multiples of i starting from i * i primeNumbersSieve[k] = false; k += i; } } } return primeNumbersSieve; };