Enhance contains function to handle arrays, undefined, and null inputs; add corresponding tests for these cases

Author: Darkidd77

Sprint-2/implement/contains.js

@@ -1,4 +1,7 @@
 function contains(obj, prop) {
+  if (Array.isArray(obj) || obj === undefined || obj === null) {
+    return false;
+  }
   return obj.hasOwnProperty(prop);
 }
 

Sprint-2/implement/contains.test.js

@@ -51,4 +51,14 @@ describe("contains", () => {
     const arr = [1, 2, 3];
     expect(contains(arr, "a")).toEqual(false);
   });
+
+  test("contains returns false for arrays, even if the index exists", () => {
+    const arr = ["a", "b", "c"];
+    expect(contains(arr, "0")).toEqual(false);
+  });
+
+  test("contains returns false for undefined", () => {
+    expect(contains(undefined, "a")).toEqual(false);
+    expect(contains(null, "a")).toEqual(false);
+  });
 });