Fix drag-performance (#1184)

* Fix drag-performance

* Fixes

* Fixes

* Fixes

* Fixes

front/src/modules/ui/board/states/selectedCardIdsSelector.ts

@@ -0,0 +1,22 @@
+import { selector } from 'recoil';
+
+import { boardCardIdsByColumnIdFamilyState } from './boardCardIdsByColumnIdFamilyState';
+import { boardColumnsState } from './boardColumnsState';
+import { isCardSelectedFamilyState } from './isCardSelectedFamilyState';
+
+export const selectedCardIdsSelector = selector<string[]>({
+  key: 'selectedCardIdsSelector',
+  get: ({ get }) => {
+    const boardColumns = get(boardColumnsState);
+
+    const cardIds = boardColumns.flatMap((boardColumn) =>
+      get(boardCardIdsByColumnIdFamilyState(boardColumn.id)),
+    );
+
+    const selectedCardIds = cardIds.filter(
+      (cardId) => get(isCardSelectedFamilyState(cardId)) === true,
+    );
+
+    return selectedCardIds;
+  },
+});