First version

src/app/groups/recent-groups-helpers.ts

@@ -0,0 +1,30 @@
+import { z } from 'zod'
+
+export const recentGroupsSchema = z.array(
+  z.object({
+    id: z.string().min(1),
+    name: z.string(),
+  }),
+)
+
+export type RecentGroups = z.infer<typeof recentGroupsSchema>
+export type RecentGroup = RecentGroups[number]
+
+const STORAGE_KEY = 'recentGroups'
+
+export function getRecentGroups() {
+  const groupsInStorageJson = localStorage.getItem(STORAGE_KEY)
+  const groupsInStorageRaw = groupsInStorageJson
+    ? JSON.parse(groupsInStorageJson)
+    : []
+  const parseResult = recentGroupsSchema.safeParse(groupsInStorageRaw)
+  return parseResult.success ? parseResult.data : []
+}
+
+export function saveRecentGroup(group: RecentGroup) {
+  const recentGroups = getRecentGroups()
+  localStorage.setItem(
+    STORAGE_KEY,
+    JSON.stringify([group, ...recentGroups.filter((rg) => rg.id !== group.id)]),
+  )
+}