diff --git a/person.tsx b/person.tsx
new file mode 100644
index 0000000..719aaba
--- /dev/null
+++ b/person.tsx
@@ -0,0 +1,11 @@
+interface IPerson {
+    name: string;
+    age: number;
+}
+ 
+function test(opt: IPerson) {
+    let key: (keyof IPerson);
+    for (key in opt) {
+        console.log(opt[key]);
+    }
+}
\ No newline at end of file