fix(i18n): add onTranslateError and fallback on defaultLocal with con…

.changeset/curly-trains-draw.md

@@ -0,0 +1,5 @@
+---
+"@scaleway/use-i18n": patch
+---
+
+add a onTranslateError function in case of desync traduction between language. This will help to focus only on default language for developers

packages/use-i18n/src/__tests__/locales/en.ts

@@ -0,0 +1,10 @@
+export default {
+  'with.identifier': 'Are you sure you want to delete {identifier}?',
+  plurals:
+    '{count, plural, =0 {No file} =1 {{count} file} other {{count} files}}',
+  subtitle: 'Here is a subtitle',
+  'tests.test.namespaces': 'test',
+  title: 'Welcome on @scaelway/ui i18n hook',
+  'translate.error':
+    'On translate sync issue with variable between locales {newVariable}',
+} as const

packages/use-i18n/src/__tests__/locales/es.ts

@@ -0,0 +1,7 @@
+export default {
+  plurals:
+    'You have {numPhotos, plural, =0 {no photos.} =1 {one photo.} other {# photos.}}',
+  subtitle: 'Aquí hay un subtítulo',
+  'tests.test.namespaces': 'test',
+  title: 'Bienvenido @scaelway/ui i18n hook',
+} as const

packages/use-i18n/src/__tests__/locales/fr.ts

@@ -0,0 +1,9 @@
+export default {
+  plurals:
+    'You have {numPhotos, plural, =0 {no photos.} =1 {one photo.} other {# photos.}}',
+  subtitle: 'Voici un sous-titre',
+  'tests.test.namespaces': 'test',
+  title: 'Bienvenue sur @scaelway/ui i18n hook',
+  'translate.error':
+    'onTranslateError fonction sera appelé car il manque une variable en français {oldFrenchVariable}',
+} as const

packages/use-i18n/src/__tests__/usei18n.tsx

@@ -9,31 +9,28 @@ import {
 import { act, renderHook, waitFor } from '@testing-library/react'
 import { enGB, fr as frDateFns } from 'date-fns/locale'
 import mockdate from 'mockdate'
-import type { ReactNode } from 'react'
+import type { ComponentProps, ReactNode } from 'react'
 import I18n, { useI18n, useTranslation } from '..'
-import en from './locales/en.json'
-import es from './locales/es.json'
-import fr from './locales/fr.json'
+import en from './locales/en'
+import es from './locales/es'
+import fr from './locales/fr'
 
 const LOCALE_ITEM_STORAGE = 'locales'
 
-type Locale = {
-  test: 'Test'
-  'with.identifier': 'Are you sure you want to delete {identifier}?'
-  plurals: '{numPhotos, plural, =0 {You have one photo.} other {You have # photos.}}'
-  subtitle: 'Here is a subtitle'
-  'tests.test.namespaces': 'test'
-  title: 'Welcome on @scaelway/ui i18n hook'
-}
-
+type LocaleEN = typeof en
+type Locale = LocaleEN
 type NamespaceLocale = {
   name: 'Name'
   lastName: 'Last Name'
   languages: 'Languages'
 }
 
+type OnTranslateError = ComponentProps<typeof I18n>['onTranslateError']
+
 const defaultSupportedLocales = ['en', 'fr', 'es']
 
+const defaultOnTranslateError: OnTranslateError = () => {}
+
 const wrapper =
   ({
     loadDateLocaleAsync = async (locale: string) => {
@@ -61,13 +58,14 @@ const wrapper =
       return enGB
     },
     defaultLoad = async ({ locale }: { locale: string }) =>
-      import(`./locales/${locale}.json`),
+      import(`./locales/${locale}.ts`),
     defaultLocale = 'en',
     defaultTranslations = {},
     enableDebugKey = false,
     enableDefaultLocale = false,
     localeItemStorage = LOCALE_ITEM_STORAGE,
     supportedLocales = defaultSupportedLocales,
+    onTranslateError = defaultOnTranslateError,
   } = {}) =>
   ({ children }: { children: ReactNode }) => (
     <I18n
@@ -80,6 +78,7 @@ const wrapper =
       enableDefaultLocale={enableDefaultLocale}
       localeItemStorage={localeItemStorage}
       supportedLocales={supportedLocales}
+      onTranslateError={onTranslateError}
     >
       {children}
     </I18n>
@@ -470,7 +469,7 @@ describe('i18n hook', () => {
     expect(localStorage.getItem(LOCALE_ITEM_STORAGE)).toBe('es')
   })
 
-  it('should translate correctly with enableDebugKey', async () => {
+  it('should translate correctly with enableDebugKey and return key', async () => {
     const { result } = renderHook(() => useI18n<Locale>(), {
       wrapper: wrapper({
         defaultLocale: 'en',
@@ -479,15 +478,66 @@ describe('i18n hook', () => {
         supportedLocales: ['en', 'fr'],
       }),
     })
+
+    // @ts-expect-error this key doesn't exist but enable debug key will return the key
     expect(result.current.t('test')).toEqual('test')
 
     await waitFor(() => {
       expect(result.current.t('title')).toEqual('title')
       expect(result.current.t('subtitle')).toEqual('subtitle')
-      expect(result.current.t('plurals', { numPhotos: 0 })).toEqual('plurals')
-      expect(result.current.t('plurals', { numPhotos: 1 })).toEqual('plurals')
-      expect(result.current.t('plurals', { numPhotos: 2 })).toEqual('plurals')
+      expect(result.current.t('plurals', { count: 0 })).toEqual('plurals')
+      expect(result.current.t('plurals', { count: 1 })).toEqual('plurals')
+      expect(result.current.t('plurals', { count: 2 })).toEqual('plurals')
+    })
+  })
+
+  it('should call onTranslateError when there is a sync issue to remove/add variable in one traduction of a language', async () => {
+    const mockOnTranslateError = jest.fn()
+
+    const { result } = renderHook(() => useI18n<Locale>(), {
+      wrapper: wrapper({
+        defaultLocale: 'en',
+        defaultTranslations: { en, fr },
+        supportedLocales: ['en', 'fr'],
+        onTranslateError: mockOnTranslateError,
+      }),
+    })
+
+    await act(async () => {
+      await result.current.switchLocale('fr')
+    })
+
+    waitFor(() => {
+      expect(result.current.currentLocale).toEqual('fr')
     })
+
+    const newVariable = 'newVariable'
+    expect(
+      result.current.t('translate.error', { newVariable: 'newVariable' }),
+    ).toBe(
+      `On translate sync issue with variable between locales ${newVariable}`,
+    )
+
+    expect(mockOnTranslateError).toHaveBeenCalledTimes(1)
+    expect(mockOnTranslateError).toHaveBeenCalledWith({
+      error: new Error(
+        'The intl string context variable "oldFrenchVariable" was not provided to the string "onTranslateError fonction sera appelé car il manque une variable en français {oldFrenchVariable}"',
+      ),
+      currentLocale: 'fr',
+      key: 'translate.error',
+      value:
+        'onTranslateError fonction sera appelé car il manque une variable en français {oldFrenchVariable}',
+    })
+
+    const oldFrenchVariable = 'cette variable fonctionne'
+    expect(
+      result.current.t('translate.error', {
+        // @ts-expect-error this variable doesn't exist in english anymore but still in french locales
+        oldFrenchVariable,
+      }),
+    ).toBe(
+      `onTranslateError fonction sera appelé car il manque une variable en français ${oldFrenchVariable}`,
+    )
   })
 
   it('should use namespaceTranslation', async () => {

packages/use-i18n/src/usei18n.tsx

@@ -200,6 +200,7 @@ const I18nContextProvider = ({
   loadDateLocaleAsync,
   localeItemStorage = LOCALE_ITEM_STORAGE,
   onLoadDateLocaleError,
+  onTranslateError,
   supportedLocales,
 }: {
   children: ReactNode
@@ -213,6 +214,17 @@ const I18nContextProvider = ({
   enableDebugKey: boolean
   localeItemStorage: string
   supportedLocales: string[]
+  onTranslateError?: ({
+    error,
+    currentLocale,
+    value,
+    key,
+  }: {
+    error: Error
+    currentLocale: string
+    value: string
+    key: string
+  }) => void
 }): ReactElement => {
   const [currentLocale, setCurrentLocale] = useState<string>(
     getCurrentLocale({ defaultLocale, localeItemStorage, supportedLocales }),
@@ -382,6 +394,7 @@ const I18nContextProvider = ({
   const translate = useCallback(
     (key: string, context?: ReactParamsObject<any>) => {
       const value = translations[currentLocale]?.[key] as string
+
       if (enableDebugKey) {
         return key
       }
@@ -390,14 +403,36 @@ const I18nContextProvider = ({
         return ''
       }
       if (context) {
-        return formatters
-          .getTranslationFormat(value, currentLocale)
-          .format(context) as string
+        try {
+          return formatters
+            .getTranslationFormat(value, currentLocale)
+            .format(context) as string
+        } catch (err) {
+          onTranslateError?.({
+            error: err as Error,
+            currentLocale,
+            value,
+            key,
+          })
+
+          // with default locale nothing should break or it's normal to not ignore it.
+          const defaultValue = translations[defaultLocale]?.[key] as string
+
+          return formatters
+            .getTranslationFormat(defaultValue, defaultLocale)
+            .format(context) as string
+        }
       }
 
       return value
     },
-    [currentLocale, translations, enableDebugKey],
+    [
+      currentLocale,
+      translations,
+      enableDebugKey,
+      defaultLocale,
+      onTranslateError,
+    ],
   )
 
   const namespaceTranslation = useCallback(