refactor(packages): change package structure

packages/react/src/hooks/useViewport.ts

@@ -0,0 +1,19 @@
+import { shallow } from 'zustand/shallow';
+import type { Viewport } from '@xyflow/system';
+
+import { useStore } from '../hooks/useStore';
+import type { ReactFlowState } from '../types';
+
+const viewportSelector = (state: ReactFlowState) => ({
+  x: state.transform[0],
+  y: state.transform[1],
+  zoom: state.transform[2],
+});
+
+function useViewport(): Viewport {
+  const viewport = useStore(viewportSelector, shallow);
+
+  return viewport;
+}
+
+export default useViewport;