Add ErrorBoundary component

src/components/ErrorBoundary.tsx

@@ -0,0 +1,23 @@
+import React from 'react';
+
+interface State { hasError: boolean; message: string; }
+
+export class ErrorBoundary extends React.Component<React.PropsWithChildren, State> {
+  state: State = { hasError: false, message: '' };
+
+  static getDerivedStateFromError(err: Error): State {
+    return { hasError: true, message: err.message };
+  }
+
+  render() {
+    if (this.state.hasError) {
+      return (
+        <div role="alert" style={{ padding: 24, color: 'var(--color-error)' }}>
+          <h2>Something went wrong</h2>
+          <pre>{this.state.message}</pre>
+        </div>
+      );
+    }
+    return this.props.children;
+  }
+}