performance

src/lib/flowUtils.ts

@@ -1,3 +1,21 @@
+/**
+ * Use as second argument to React.memo() for node components.
+ * Skips re-render when only position (or other unrelated props) changed,
+ * so dragging one node doesn't force other nodes to re-render.
+ */
+export function nodePropsAreEqual<P extends { id?: string; data?: any; width?: number; height?: number; selected?: boolean }>(
+  prev: P,
+  next: P
+): boolean {
+  return (
+    prev.id === next.id &&
+    prev.data === next.data &&
+    prev.width === next.width &&
+    prev.height === next.height &&
+    prev.selected === next.selected
+  )
+}
+
 export const PREFIX_BY_TYPE: Record<string, string> = {
   config: 'cfg_',
   render: 'rnd_',