Here's a simple way to check if element in an array is a prime number.

const array = [-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13];

function isPrime(n) {
  if (n<=1) return false

  if (n==2) return true

  for (var i=2; i<n; i++) {
      if (n%i==0) return false
  }

  return true
}

console.log(array.filter(isPrime))

From this we get

[2, 3, 5, 7, 11, 13]

those numbers that are prime.

Let's go through this step-by-step.

First, we know that negative numbers are excluded. Also number 1 is excluded because by definition a prime is one that is divisible only by one and itself that is not 1.

Number 2 is a prime so let's include that.

Now the main bit (the for loop). Let's say the number being tested is called n. Then need to test for number i: 2<i<n-1, whether n%i!=0. If n%i==0 for any i, then n is not a prime.

Lastly, if it passes all tests then return true.

Now for the filter function of js. We simply pass function isPrime as callback function to it.

That's it! :)