Finished task

src/App.tsx

@@ -1,7 +1,31 @@
 import React from 'react';
 
-export const App: React.FC = () => (
-  <div className="App">
-    <p className="App__message">The last pressed key is [Enter]</p>
-  </div>
-);
+export class App extends React.PureComponent {
+  state = {
+    pressedKey: '',
+  };
+
+  componentDidMount(): void {
+    document.addEventListener('keyup', (event: KeyboardEvent) => {
+      this.setState({ pressedKey: event.key });
+    });
+  }
+
+  componentWillUnmount(): void {
+    document.removeEventListener('keyup', this.setState);
+  }
+
+  render() {
+    return (
+      <div className="App">
+        <p className="App__message">
+          {
+            !this.state.pressedKey
+              ? 'Nothing was pressed yet'
+              : `The last pressed key is [${this.state.pressedKey}]`
+          }
+        </p>
+      </div>
+    );
+  }
+}