feat: add hydrate data type-safe helper

Signed-off-by: Innei <tukon479@gmail.com>

apps/server/client/lib/helper.ts

@@ -2,6 +2,9 @@ import { setOpenInAppDeeplink } from "@client/atoms/app"
 import type { FeedOrListRespModel } from "@follow/models/types"
 import { DEEPLINK_SCHEME } from "@follow/shared/constants"
 
+import type { ApiClient } from "~/lib/api-client"
+import type { defineMetadata } from "~/meta-handler"
+
 export const getPreferredTitle = (feed?: FeedOrListRespModel | null) => {
   if (!feed?.id) {
     return feed?.title
@@ -14,6 +17,44 @@ export const getHydrateData = (key: string) => {
   return window.__HYDRATE__?.[key]
 }
 
+// type ExtractHydrateData<T> = T extends readonly (infer Item)[]
+//   ? Item extends { readonly type: "hydrate"; readonly data: infer D }
+//     ? D
+//     : never
+//   : never
+
+// export type GetHydrateData<T> = T extends (...args: any[]) => Promise<infer R>
+//   ? ExtractHydrateData<R>
+//   : T extends Promise<infer R>
+//     ? ExtractHydrateData<R>
+//     : ExtractHydrateData<T>
+
+type ExtractHydrateData<T> = T extends readonly (infer Item)[]
+  ? Item extends { readonly type: "hydrate"; readonly data: infer D }
+    ? D
+    : never
+  : never
+
+type UnwrapMetadataFn<T> =
+  T extends <P extends Record<string, string>>(args: {
+    params: P
+    apiClient: ApiClient
+    origin: string
+    throwError: (status: number, message: any) => never
+  }) => Promise<infer R> | infer R
+    ? R
+    : never
+
+export type GetHydrateData<T> = T extends (...args: any[]) => Promise<infer R>
+  ? ExtractHydrateData<R>
+  : T extends (...args: any[]) => infer R
+    ? ExtractHydrateData<R>
+    : T extends Promise<infer R>
+      ? ExtractHydrateData<R>
+      : T extends typeof defineMetadata
+        ? ExtractHydrateData<UnwrapMetadataFn<Parameters<T>[0]>>
+        : ExtractHydrateData<T>
+
 export const askOpenInFollowApp = (deeplink: string, fallback?: () => string): Promise<boolean> => {
   return new Promise(() => {
     const deeplinkUrl = `${DEEPLINK_SCHEME}${deeplink}`

apps/server/client/pages/(main)/share/feeds/[id]/metadata.ts

@@ -1,6 +1,8 @@
+import type { GetHydrateData } from "@client/lib/helper"
+
 import { defineMetadata } from "~/meta-handler"
 
-export default defineMetadata(async ({ params, apiClient, origin, throwError }) => {
+const meta = defineMetadata(async ({ params, apiClient, origin, throwError }) => {
   const feedId = params.id
 
   const feed = await apiClient.feeds.$get({ query: { id: feedId } }).catch((e) => {
@@ -27,5 +29,8 @@ export default defineMetadata(async ({ params, apiClient, origin, throwError })
       path: apiClient.feeds.$url({ query: { id: feedId } }).pathname,
       key: `feeds.$get,query:id=${feedId}`,
     },
-  ]
+  ] as const
 })
+
+export type FeedHydrateData = GetHydrateData<typeof meta>
+export default meta

apps/server/client/query/feed.ts

@@ -1,5 +1,6 @@
 import { apiClient } from "@client/lib/api-fetch"
 import { getHydrateData } from "@client/lib/helper"
+import type { FeedHydrateData } from "@client/pages/(main)/share/feeds/[id]/metadata"
 import { useQuery } from "@tanstack/react-query"
 
 async function fetchFeedById(id: string) {
@@ -14,9 +15,7 @@ export const useFeed = ({ id }: { id: string }) =>
   useQuery({
     queryKey: ["feed", id],
     queryFn: () => fetchFeedById(id),
-    initialData: getHydrateData(`feeds.$get,query:id=${id}`) as any as Awaited<
-      ReturnType<typeof fetchFeedById>
-    >,
+    initialData: getHydrateData(`feeds.$get,query:id=${id}`) as FeedHydrateData,
   })
 
 export type Feed = Awaited<ReturnType<typeof fetchFeedById>>

apps/server/src/meta-handler.ts

@@ -68,22 +68,20 @@ export async function injectMetaHandler(
   return []
 }
 
-export function defineMetadata<Params extends Record<string, string>>(
+export function defineMetadata<Params extends Record<string, string>, T extends readonly MetaTag[]>(
   fn: (args: {
     req: FastifyRequest
     url: URL
     params: Params
     apiClient: ApiClient
     origin: string
-
     setStatus: (status: number) => void
     setStatusText: (statusText: string) => void
     throwError: (status: number, message: any) => never
-  }) => MetaTag[] | Promise<MetaTag[]>,
+  }) => Promise<T> | T,
 ) {
   return fn
 }
-
 export class MetaError extends Error {
   status: number
   metaMessage: object