feat(core,composables): add useNodesInitialized composable

packages/core/src/composables/useNodesInitialized.ts

@@ -0,0 +1,26 @@
+import { computed } from 'vue'
+import { useVueFlow } from './useVueFlow'
+
+export interface UseNodesInitializedOptions {
+  includeHiddenNodes?: boolean
+}
+
+export function useNodesInitialized(options: UseNodesInitializedOptions = { includeHiddenNodes: false }) {
+  const { nodes } = useVueFlow()
+
+  return computed(() => {
+    if (nodes.value.length === 0) {
+      return false
+    }
+
+    for (const node of nodes.value) {
+      if (options.includeHiddenNodes || !node.hidden) {
+        if (node?.handleBounds === undefined) {
+          return false
+        }
+      }
+    }
+
+    return true
+  })
+}