feature: caching

src/fetch/announcement.ts

@@ -1,7 +1,10 @@
 import { getPayload } from 'payload'
+import { unstable_cache } from 'next/cache'
 import config from '@/payload.config'
 import { Announcement, Parish } from '@/payload-types'
 
+const CACHE_TTL = 300 // 5 minutes
+
 /**
  * Fetch last announcement for a parish
  */
@@ -45,9 +48,8 @@ export const fetchLastAnnouncement = async (
 /**
  * Fetch the last announcement for each parish
  */
-export const fetchLastAnnouncements = async (): Promise<
-  Array<{ parish: Parish; doc: Announcement }>
-> => {
+export const fetchLastAnnouncements = unstable_cache(
+  async (): Promise<Array<{ parish: Parish; doc: Announcement }>> => {
     const payload = await getPayload({ config })
     const parishes = await payload.find({ collection: 'parish', limit: 100 })
 
@@ -61,4 +63,7 @@ export const fetchLastAnnouncements = async (): Promise<
     return results.filter(
       (r): r is { parish: Parish; doc: Announcement } => !!r,
     )
-}
+  },
+  ['fetchLastAnnouncements'],
+  { revalidate: CACHE_TTL },
+)

src/fetch/calendar.ts

@@ -1,7 +1,10 @@
 import { getPayload } from 'payload'
+import { unstable_cache } from 'next/cache'
 import config from '@/payload.config'
 import { Calendar, Parish } from '@/payload-types'
 
+const CACHE_TTL = 300 // 5 minutes
+
 /**
  * Fetch last calendar for a parish
  */
@@ -45,9 +48,8 @@ export const fetchLastCalendar = async (
 /**
  * Fetch the last calendar for each parish
  */
-export const fetchLastCalendars = async (): Promise<
-  Array<{ parish: Parish; doc: Calendar }>
-> => {
+export const fetchLastCalendars = unstable_cache(
+  async (): Promise<Array<{ parish: Parish; doc: Calendar }>> => {
     const payload = await getPayload({ config })
     const parishes = await payload.find({ collection: 'parish', limit: 100 })
 
@@ -61,4 +63,7 @@ export const fetchLastCalendars = async (): Promise<
     return results.filter(
       (r): r is { parish: Parish; doc: Calendar } => !!r,
     )
-}
+  },
+  ['fetchLastCalendars'],
+  { revalidate: CACHE_TTL },
+)

src/fetch/worship.ts

@@ -1,29 +1,39 @@
 import { getPayload, PaginatedDocs } from 'payload'
+import { unstable_cache } from 'next/cache'
 import config from '@/payload.config'
 import { Worship } from '@/payload-types'
 
+const CACHE_TTL = 300 // 5 minutes
+
 type FetchWorshipArgs = {
   fromDate?: Date
   tillDate?: Date
   locations?: string[]
 }
 
-export const fetchWorship = async (
-  args?: FetchWorshipArgs,
-): Promise<PaginatedDocs<Worship>> => {
-  const { fromDate, tillDate, locations } = args || {}
-
-  let date = fromDate
-  if (!date) {
-    date = new Date()
-    date.setHours(0, 0, 0, 0)
+// Resolved args use ISO strings so they serialize into a stable cache key.
+type ResolvedWorshipArgs = {
+  fromDate: string
+  tillDate?: string
+  locations?: string[]
 }
 
+// Round down to the cache window so millisecond-precision dates produce a
+// stable key for the duration of the TTL.
+function roundDownToTtl(date: Date): Date {
+  const ms = CACHE_TTL * 1000
+  return new Date(Math.floor(date.getTime() / ms) * ms)
+}
+
+const getWorship = unstable_cache(
+  async (args: ResolvedWorshipArgs): Promise<PaginatedDocs<Worship>> => {
+    const { fromDate, tillDate, locations } = args
+
     const query: any = {
       and: [
         {
           date: {
-          greater_than_equal: date.toISOString(),
+            greater_than_equal: fromDate,
           },
         },
       ],
@@ -32,7 +42,7 @@ export const fetchWorship = async (
     if (tillDate) {
       query.and.push({
         date: {
-        less_than: tillDate.toISOString(),
+          less_than: tillDate,
         },
       })
     }
@@ -59,6 +69,27 @@ export const fetchWorship = async (
       },
       limit: 100,
     }) as Promise<PaginatedDocs<Worship>>
+  },
+  ['fetchWorship'],
+  { revalidate: CACHE_TTL },
+)
+
+export const fetchWorship = async (
+  args?: FetchWorshipArgs,
+): Promise<PaginatedDocs<Worship>> => {
+  const { fromDate, tillDate, locations } = args || {}
+
+  let date = fromDate
+  if (!date) {
+    date = new Date()
+    date.setHours(0, 0, 0, 0)
+  }
+
+  return getWorship({
+    fromDate: roundDownToTtl(date).toISOString(),
+    tillDate: tillDate ? roundDownToTtl(tillDate).toISOString() : undefined,
+    locations,
+  })
 }
 
 /**