Added sum of primes in JavaScript

challenges/sum_of_primes/script.js

@@ -0,0 +1,32 @@
+// Sum of Primes
+
+// Find the sum of primes below n.
+
+ sumOfPrimes = () => {
+    let num = parseInt(prompt('Enter a number'))
+    // create array
+    let newArr = []
+
+    // check if number is prime
+    function isPrime(num){
+        if (num === 2) {
+            return true;
+            }
+
+        for(let i = 2; i < num; i++ ) {
+            if( num % i === 0) return false;
+        }  
+        return true;
+    }
+    // push prime numbers to array
+    for(let i = 2; i <= num; i++){
+        if(isPrime(i)){
+            newArr.push(i)
+        } 
+    }
+    return newArr.reduce((a,b) => a + b, 0)
+
+    }
+
+    sumOfPrimes();
+