feat(next): strongly type getNextRequestI18n (#7157)

Fixes #7137

Author: AlessioGr

packages/next/src/utilities/getNextRequestI18n.ts

@@ -1,4 +1,10 @@
-import type { I18n } from '@payloadcms/translations'
+import type {
+  ClientTranslationsObject,
+  DefaultTranslationKeys,
+  DefaultTranslationsObject,
+  I18n,
+  I18nClient,
+} from '@payloadcms/translations'
 import type { SanitizedConfig } from 'payload'
 
 import { initI18n } from '@payloadcms/translations'
@@ -11,9 +17,23 @@ import { getRequestLanguage } from './getRequestLanguage.js'
  *
  * It must be called on the server side, and within the lifecycle of a request since it relies on the request headers and cookies.
  */
-export const getNextRequestI18n = async ({ config }: { config: SanitizedConfig }): Promise<I18n> =>
-  initI18n({
+export const getNextRequestI18n = async <
+  TAdditionalTranslations = {},
+  TAdditionalClientTranslationKeys extends string = never,
+>({
+  config,
+}: {
+  config: SanitizedConfig
+}): Promise<
+  [TAdditionalClientTranslationKeys] extends [never]
+    ? I18nClient
+    : TAdditionalTranslations extends object
+      ? I18nClient<TAdditionalTranslations, TAdditionalClientTranslationKeys>
+      : I18nClient<ClientTranslationsObject, TAdditionalClientTranslationKeys>
+> => {
+  return (await initI18n({
     config: config.i18n,
     context: 'client',
     language: getRequestLanguage({ config, cookies: cookies(), headers: headers() }),
-  })
+  })) as any
+}

packages/next/src/views/NotFound/meta.ts

@@ -1,4 +1,4 @@
-import type { I18n } from '@payloadcms/translations'
+import type { I18nClient } from '@payloadcms/translations'
 import type { Metadata } from 'next'
 import type { SanitizedConfig } from 'payload'
 
@@ -9,7 +9,7 @@ export const generateNotFoundMeta = async ({
   i18n,
 }: {
   config: SanitizedConfig
-  i18n: I18n
+  i18n: I18nClient
 }): Promise<Metadata> =>
   meta({
     description: i18n.t('general:pageNotFound'),

packages/next/src/views/Root/index.tsx

@@ -1,4 +1,4 @@
-import type { I18n } from '@payloadcms/translations'
+import type { I18nClient } from '@payloadcms/translations'
 import type { Metadata } from 'next'
 import type { SanitizedConfig } from 'payload'
 
@@ -15,7 +15,7 @@ export { generatePageMetadata } from './meta.js'
 
 export type GenerateViewMetadata = (args: {
   config: SanitizedConfig
-  i18n: I18n
+  i18n: I18nClient
   isEditing?: boolean
   params?: { [key: string]: string | string[] }
 }) => Promise<Metadata>