refactor(frontend): extract reusable hooks and page helper modules

vite-frontend/src/utils/order-storage.ts

@@ -0,0 +1,57 @@
+const parseOrderIds = (rawValue: string | null): number[] | null => {
+  if (!rawValue) {
+    return null;
+  }
+
+  try {
+    const parsed = JSON.parse(rawValue);
+
+    if (!Array.isArray(parsed)) {
+      return null;
+    }
+
+    return parsed
+      .map((id) => Number(id))
+      .filter((id) => Number.isInteger(id) && id >= 0);
+  } catch {
+    return null;
+  }
+};
+
+export const loadStoredOrder = (
+  storageKey: string,
+  sourceIds: number[],
+): number[] => {
+  const parsed = parseOrderIds(localStorage.getItem(storageKey));
+
+  if (!parsed || parsed.length === 0) {
+    return sourceIds;
+  }
+
+  const idSet = new Set(sourceIds);
+  const validIds: number[] = [];
+
+  parsed.forEach((id) => {
+    if (idSet.has(id) && !validIds.includes(id)) {
+      validIds.push(id);
+    }
+  });
+
+  if (validIds.length === 0) {
+    return sourceIds;
+  }
+
+  sourceIds.forEach((id) => {
+    if (!validIds.includes(id)) {
+      validIds.push(id);
+    }
+  });
+
+  return validIds;
+};
+
+export const saveOrder = (storageKey: string, ids: number[]): void => {
+  try {
+    localStorage.setItem(storageKey, JSON.stringify(ids));
+  } catch {}
+};