add sum function

functions.js

@@ -0,0 +1,5 @@
+function sum(a, b) {
+  return a + b;
+}
+
+module.exports = { sum };

test.js

@@ -1,2 +1,6 @@
+// import { sum } from "./functions";
+const { sum } = require("./functions");
 const a = 22;
-console.log('sum', a);
+const b = 23;
+
+console.log("sum", sum(a, b));