Update gcd.js

Author: varun93

gcd.js

@@ -3,7 +3,7 @@ const euclideanGCD = (a, b) => {
     return a;
   }
   // swap if a is lesser than b
-  if (b > a) {
+  if (a < b) {
     a = a ^ b;
     b = a ^ b;
     a = a ^ b;
@@ -16,6 +16,6 @@ const gcd = (a, b) => {
   if (b === 0) return a;
 
   for (let i = Math.min(a, b) >> 1; i >= 1; i--) {
-    if (a % i === 0 && b % i === 0) return i;
+   	if(!(a%i) && !(b%i))  return i;
   }
 };