30-seconds-of-code/snippets/isPrime.md

isPrime

Checks if the provided integer is a prime number.

Returns false if the provided number has positive divisors other than 1 and itself or if the number itself is less than 2.

const isPrime = num => {
  for (var i = 2; i * i <= num; i++) if (num % i == 0) return false;
  return num >= 2;
};
// isPrime(11) -> true
// isPrime(12) -> false