// how to find prime numbers in an array in javascript
let num = [-1,-2,-3,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];
let result = [];
function isPrime(num) {
if(num < 2) return false;
for (let k = 2; k < num; k++){
if(num % k == 0){
return false;
}
}
return true;
}
num.forEach(function (element) {
const item = isPrime(element);
if (item) {
result.push(element);
}
});
console.log(result); // [ 2, 3, 5, 7, 11, 13, 17, 19]