feat(hooks): add useNodesInitialized

packages/core/src/hooks/useNodesInitialized.ts

@@ -0,0 +1,12 @@
+import { ReactFlowState } from '../types';
+import { useStore } from './useStore';
+
+const selector = (s: ReactFlowState) => Array.from(s.nodeInternals.values()).every((n) => n.width && n.height);
+
+function useNodesInitialized(): boolean {
+  const initialized = useStore(selector);
+
+  return initialized;
+}
+
+export default useNodesInitialized;

packages/core/src/index.ts

@@ -41,5 +41,7 @@ export { default as useKeyPress } from './hooks/useKeyPress';
 export * from './hooks/useNodesEdgesState';
 export { useStore, useStoreApi } from './hooks/useStore';
 export { default as useOnViewportChange } from './hooks/useOnViewportChange';
+export { default as useOnSelectionChange } from './hooks/useOnSelectionChange';
+export { default as useNodesInitialized } from './hooks/useNodesInitialized';
 
 export * from './types';