diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..23fd35f
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "editor.formatOnSave": true
+}
\ No newline at end of file
diff --git a/WebComponent.mjs b/WebComponent.mjs
index ac1b0c4..3ef10c5 100644
--- a/WebComponent.mjs
+++ b/WebComponent.mjs
@@ -20,7 +20,7 @@ export class WebComponent extends HTMLElement {
       this.render();
     }
 
-    this.onChanges({previousValue, currentValue});
+    this.onChanges({ previousValue, currentValue });
   }
 
   render() {
diff --git a/demo/SimpleText.mjs b/demo/SimpleText.mjs
new file mode 100644
index 0000000..b866872
--- /dev/null
+++ b/demo/SimpleText.mjs
@@ -0,0 +1,16 @@
+// @ts-check
+import WebComponent from "../index.mjs";
+
+class SimpleText extends WebComponent {
+  greeting = "Hello";
+
+  static get observedAttributes() {
+    return ["greeting"];
+  }
+
+  get template() {
+    return `<p>Simple text ${this.greeting}</p>`;
+  }
+}
+
+customElements.define("simple-text", SimpleText);
diff --git a/demo/index.html b/demo/index.html
index 17b26bd..07855ea 100644
--- a/demo/index.html
+++ b/demo/index.html
@@ -1,12 +1,21 @@
-<head>
-  <script type="module" src="HelloWorld.mjs"></script>
-</head>
-<body>
-  <hello-world name="Ayo" emotion="sad">
-  <script>
-      const helloWorld = document.querySelector('hello-world');
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>WC demo</title>
+    <script type="module" src="HelloWorld.mjs"></script>
+    <script type="module" src="SimpleText.mjs"></script>
+  </head>
+  <body>
+    <hello-world name="Ayo" emotion="sad"></hello-world>
+    <simple-text greeting="hey"></simple-text>
+
+    <script type="module">
+      const helloWorld = document.querySelector("hello-world");
       setTimeout(() => {
-        helloWorld.setAttribute('emotion', 'excited');
-      }, 2500)
-  </script>
-</body>
\ No newline at end of file
+        helloWorld.setAttribute("emotion", "excited");
+      }, 2500);
+    </script>
+  </body>
+</html>
