diff --git a/src/App.tsx b/src/App.tsx
index 33c4e71da..934ff41f4 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -1,8 +1,37 @@
 import React from 'react';
-import Message from './components/Message';
 
-export const App: React.FC = () => (
-  <div className="App">
-    <Message />
-  </div>
-);
+type State = {
+  currentKey: string | null;
+};
+
+export class App extends React.Component {
+  state: State = {
+    currentKey: null,
+  };
+
+  componentDidMount() {
+    document.addEventListener('keyup', (event: KeyboardEvent) => {
+      this.setState({ currentKey: event.key });
+    });
+  }
+
+  componentWillUnmount() {
+    document.removeEventListener('keyup', (event: KeyboardEvent) => {
+      this.setState({ currentKey: event.key });
+    });
+  }
+
+  render() {
+    const { currentKey } = this.state;
+
+    return (
+      <div className="App">
+        <p className="App__message">
+          {currentKey
+            ? `The last pressed key is[${currentKey}]`
+            : 'Nothing was pressed yet'}
+        </p>
+      </div>
+    );
+  }
+}
diff --git a/src/components/Message.tsx b/src/components/Message.tsx
deleted file mode 100644
index 4c792fa08..000000000
--- a/src/components/Message.tsx
+++ /dev/null
@@ -1,37 +0,0 @@
-import React from 'react';
-
-type State = {
-  currentKey: string | null;
-};
-
-class Message extends React.Component {
-  state: State = {
-    currentKey: null,
-  };
-
-  componentDidMount() {
-    document.addEventListener('keyup', (event: KeyboardEvent) => {
-      this.setState({ currentKey: event.key });
-    });
-  }
-
-  componentWillUnmount() {
-    document.removeEventListener('keyup', (event: KeyboardEvent) => {
-      this.setState({ currentKey: event.key });
-    });
-  }
-
-  render() {
-    const { currentKey } = this.state;
-
-    return (
-      <p className="App__message">
-        {currentKey
-          ? `The last pressed key is[${currentKey}]`
-          : 'Nothing was pressed yet'}
-      </p>
-    );
-  }
-}
-
-export default Message;