Updated the test system

test/reducedFilter.test.js

@@ -0,0 +1,23 @@
+const expect = require('expect');
+const {reducedFilter} = require('./_30s.js');
+
+test('reducedFilter is a Function', () => {
+  expect(reducedFilter).toBeInstanceOf(Function);
+});
+const data = [
+  {
+    id: 1,
+    name: 'john',
+    age: 24
+  },
+  {
+    id: 2,
+    name: 'mike',
+    age: 50
+  }
+];
+test('Filter an array of objects based on a condition while also filtering out unspecified keys.', () => {
+  expect(reducedFilter(data, ['id', 'name'], item => item.age > 24)).toEqual([
+    { id: 2, name: 'mike' }
+  ]);
+});