1// This seems to be the most common and comprehensive means
2// of implementing a 'is a number a prime function' in javascript 
3// if you would like t0 learn more complex , but efficient algorithms. 
4// Visit the link below
5// https://stackoverflow.com/questions/11966520/how-to-find-prime-numbers-between-0-100
6
7function isPrime(num) {
8  if(num < 2) return false;
9
10  for (let k = 2; k < num; k++){
11    if( num % k == 0){
12      return false;
13    }
14  }
15  return true;
16}

1//#Source https://bit.ly/2neWfJ2 
2const isPrime = num => {
3  const boundary = Math.floor(Math.sqrt(num));
4  for (var i = 2; i <= boundary; i++) if (num % i === 0) return false;
5  return num >= 2;
6};
7
8console.log(isPrime(11));
9console.log(isPrime(17));
10console.log(isPrime(8));
11
12