feat(app): support locale plural rules (#40370)

Co-authored-by: Luke Parker <10430890+Hona@users.noreply.github.com>

packages/ui/src/context/i18n.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, test } from "bun:test"
+import { pluralCategory } from "./i18n"
+
+describe("pluralCategory", () => {
+  test.each([
+    ["en", 0, "other"],
+    ["en", 1, "one"],
+    ["fr", 0, "one"],
+    ["fr", 1_000_000, "many"],
+    ["ru", 1, "one"],
+    ["ru", 2, "few"],
+    ["ru", 5, "many"],
+    ["ru", 21, "one"],
+    ["ar", 0, "zero"],
+    ["ar", 1, "one"],
+    ["ar", 2, "two"],
+    ["ar", 3, "few"],
+    ["ar", 11, "many"],
+    ["ar", 100, "other"],
+    ["ja", 1, "other"],
+  ] as const)("selects %s for %d as %s", (locale, count, expected) => {
+    expect(pluralCategory(locale, count)).toBe(expected)
+  })
+})

packages/ui/src/context/i18n.tsx

@@ -3,11 +3,37 @@ import { dict as en } from "../i18n/en"
 
 export type UiI18nKey = keyof typeof en
 
+export const UI_PLURAL_KEYS = [
+  "ui.sessionTurn.diffs.changed",
+  "ui.messagePart.context.read",
+  "ui.messagePart.context.search",
+  "ui.messagePart.context.list",
+] as const
+export type UiI18nPluralKey = (typeof UI_PLURAL_KEYS)[number]
+export type UiPluralCategory = "zero" | "one" | "two" | "few" | "many" | "other"
+export type UiI18nPluralLookupKey = `${UiI18nPluralKey}.${UiPluralCategory}`
+
 export type UiI18nParams = Record<string, string | number | boolean>
 
 export type UiI18n = {
   locale: Accessor<string>
   t: (key: UiI18nKey, params?: UiI18nParams) => string
+  plural: (key: UiI18nPluralKey, count: number, params?: UiI18nParams) => string
+}
+
+const rules = new Map<string, Intl.PluralRules>()
+
+export function pluralCategory(locale: string, count: number): UiPluralCategory {
+  const cached = rules.get(locale)
+  if (cached) return cached.select(count)
+  const next = new Intl.PluralRules(locale)
+  if (rules.size >= 32) rules.delete(rules.keys().next().value!)
+  rules.set(locale, next)
+  return next.select(count)
+}
+
+export function pluralKey(key: UiI18nPluralKey, category: UiPluralCategory) {
+  return `${key}.${category}` as UiI18nPluralLookupKey
 }
 
 function resolveTemplate(text: string, params?: UiI18nParams) {
@@ -25,6 +51,8 @@ const fallback: UiI18n = {
     const value = en[key] ?? String(key)
     return resolveTemplate(value, params)
   },
+  plural: (key, count, params) =>
+    fallback.t(pluralKey(key, pluralCategory(fallback.locale(), count)), { ...params, count }),
 }
 
 const Context = createContext<UiI18n>(fallback)

packages/ui/src/i18n/ar.ts

@@ -57,6 +57,10 @@ export const dict = {
   "ui.sessionTurn.summary.response": "استجابة",
   "ui.sessionTurn.diff.showMore": "إظهار المزيد من التغييرات ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "ملف معدل: {{count}}",
+  "ui.sessionTurn.diffs.changed.zero": "الملفات المعدلة: {{count}}",
+  "ui.sessionTurn.diffs.changed.two": "عدد الملفات المعدلة: {{count}}",
+  "ui.sessionTurn.diffs.changed.few": "الملفات المعدلة: {{count}}",
+  "ui.sessionTurn.diffs.changed.many": "الملفات المعدلة: {{count}}",
   "ui.sessionTurn.diffs.changed.other": "الملفات المعدلة: {{count}}",
   "ui.sessionTurn.diffs.showAll": "إظهار الكل",
   "ui.sessionTurn.diffs.showLess": "إظهار عدد أقل",
@@ -95,10 +99,22 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "تم إهمال الأسئلة",
   "ui.messagePart.compaction": "تم اختصار الجلسة",
   "ui.messagePart.context.read.one": "{{count}} قراءة",
+  "ui.messagePart.context.read.zero": "{{count}} قراءة",
+  "ui.messagePart.context.read.two": "عدد القراءات: {{count}}",
+  "ui.messagePart.context.read.few": "{{count}} قراءات",
+  "ui.messagePart.context.read.many": "{{count}} قراءةً",
   "ui.messagePart.context.read.other": "{{count}} قراءات",
   "ui.messagePart.context.search.one": "{{count}} بحث",
+  "ui.messagePart.context.search.zero": "{{count}} عملية بحث",
+  "ui.messagePart.context.search.two": "عدد عمليات البحث: {{count}}",
+  "ui.messagePart.context.search.few": "{{count}} عمليات بحث",
+  "ui.messagePart.context.search.many": "{{count}} عملية بحث",
   "ui.messagePart.context.search.other": "{{count}} عمليات بحث",
   "ui.messagePart.context.list.one": "{{count}} عملية سرد",
+  "ui.messagePart.context.list.zero": "{{count}} عملية سرد",
+  "ui.messagePart.context.list.two": "عدد عمليات السرد: {{count}}",
+  "ui.messagePart.context.list.few": "{{count}} عمليات سرد",
+  "ui.messagePart.context.list.many": "{{count}} عملية سرد",
   "ui.messagePart.context.list.other": "{{count}} عمليات سرد",
   "ui.messagePart.diagnostic.error": "خطأ",
   "ui.messagePart.title.edit": "تحرير",

packages/ui/src/i18n/br.ts

@@ -57,6 +57,7 @@ export const dict = {
   "ui.sessionTurn.summary.response": "Resposta",
   "ui.sessionTurn.diff.showMore": "Mostrar mais alterações ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "Arquivo alterado: {{count}}",
+  "ui.sessionTurn.diffs.changed.many": "Arquivos alterados: {{count}}",
   "ui.sessionTurn.diffs.changed.other": "Arquivos alterados: {{count}}",
   "ui.sessionTurn.diffs.showAll": "Mostrar tudo",
   "ui.sessionTurn.diffs.showLess": "Mostrar menos",
@@ -95,10 +96,13 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "Perguntas descartadas",
   "ui.messagePart.compaction": "Sessão compactada",
   "ui.messagePart.context.read.one": "{{count}} leitura",
+  "ui.messagePart.context.read.many": "{{count}} de leituras",
   "ui.messagePart.context.read.other": "{{count}} leituras",
   "ui.messagePart.context.search.one": "{{count}} pesquisa",
+  "ui.messagePart.context.search.many": "{{count}} de pesquisas",
   "ui.messagePart.context.search.other": "{{count}} pesquisas",
   "ui.messagePart.context.list.one": "{{count}} lista",
+  "ui.messagePart.context.list.many": "{{count}} de listas",
   "ui.messagePart.context.list.other": "{{count}} listas",
   "ui.messagePart.diagnostic.error": "Erro",
   "ui.messagePart.title.edit": "Editar",

packages/ui/src/i18n/bs.ts

@@ -61,6 +61,7 @@ export const dict = {
   "ui.sessionTurn.summary.response": "Odgovor",
   "ui.sessionTurn.diff.showMore": "Prikaži još izmjena ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "{{count}} izmijenjena datoteka",
+  "ui.sessionTurn.diffs.changed.few": "{{count}} izmijenjene datoteke",
   "ui.sessionTurn.diffs.changed.other": "{{count}} izmijenjene datoteke",
   "ui.sessionTurn.diffs.showAll": "Prikaži sve",
   "ui.sessionTurn.diffs.showLess": "Prikaži manje",
@@ -99,10 +100,13 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "Pitanja odbačena",
   "ui.messagePart.compaction": "Sesija sažeta",
   "ui.messagePart.context.read.one": "{{count}} čitanje",
+  "ui.messagePart.context.read.few": "{{count}} čitanja",
   "ui.messagePart.context.read.other": "{{count}} čitanja",
   "ui.messagePart.context.search.one": "{{count}} pretraga",
+  "ui.messagePart.context.search.few": "{{count}} pretrage",
   "ui.messagePart.context.search.other": "{{count}} pretrage",
   "ui.messagePart.context.list.one": "{{count}} listanje",
+  "ui.messagePart.context.list.few": "{{count}} listanja",
   "ui.messagePart.context.list.other": "{{count}} listanja",
   "ui.messagePart.diagnostic.error": "Greška",
   "ui.messagePart.title.edit": "Uredi",

packages/ui/src/i18n/es.ts

@@ -57,6 +57,7 @@ export const dict = {
   "ui.sessionTurn.summary.response": "Respuesta",
   "ui.sessionTurn.diff.showMore": "Mostrar más cambios ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "{{count}} archivo modificado",
+  "ui.sessionTurn.diffs.changed.many": "{{count}} de archivos modificados",
   "ui.sessionTurn.diffs.changed.other": "{{count}} archivos modificados",
   "ui.sessionTurn.diffs.showAll": "Mostrar todos",
   "ui.sessionTurn.diffs.showLess": "Mostrar menos",
@@ -95,10 +96,13 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "Preguntas descartadas",
   "ui.messagePart.compaction": "Sesión compactada",
   "ui.messagePart.context.read.one": "{{count}} lectura",
+  "ui.messagePart.context.read.many": "{{count}} de lecturas",
   "ui.messagePart.context.read.other": "{{count}} lecturas",
   "ui.messagePart.context.search.one": "{{count}} búsqueda",
+  "ui.messagePart.context.search.many": "{{count}} de búsquedas",
   "ui.messagePart.context.search.other": "{{count}} búsquedas",
   "ui.messagePart.context.list.one": "{{count}} listado",
+  "ui.messagePart.context.list.many": "{{count}} de listados",
   "ui.messagePart.context.list.other": "{{count}} listados",
   "ui.messagePart.diagnostic.error": "Error",
   "ui.messagePart.title.edit": "Editar",

packages/ui/src/i18n/fr.ts

@@ -58,6 +58,7 @@ export const dict = {
   "ui.sessionTurn.summary.response": "Réponse",
   "ui.sessionTurn.diff.showMore": "Afficher plus de modifications ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "Fichier modifié : {{count}}",
+  "ui.sessionTurn.diffs.changed.many": "Fichiers modifiés : {{count}}",
   "ui.sessionTurn.diffs.changed.other": "Fichiers modifiés : {{count}}",
   "ui.sessionTurn.diffs.showAll": "Tout afficher",
   "ui.sessionTurn.diffs.showLess": "Afficher moins",
@@ -96,10 +97,13 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "Questions ignorées",
   "ui.messagePart.compaction": "Session compactée",
   "ui.messagePart.context.read.one": "{{count}} lecture",
+  "ui.messagePart.context.read.many": "{{count}} de lectures",
   "ui.messagePart.context.read.other": "{{count}} lectures",
   "ui.messagePart.context.search.one": "{{count}} recherche",
+  "ui.messagePart.context.search.many": "{{count}} de recherches",
   "ui.messagePart.context.search.other": "{{count}} recherches",
   "ui.messagePart.context.list.one": "{{count}} liste",
+  "ui.messagePart.context.list.many": "{{count}} de listes",
   "ui.messagePart.context.list.other": "{{count}} listes",
   "ui.messagePart.diagnostic.error": "Erreur",
   "ui.messagePart.title.edit": "Modifier",

packages/ui/src/i18n/it.ts

@@ -56,6 +56,7 @@ export const dict: Record<string, string> = {
   "ui.sessionTurn.summary.response": "Risposta",
   "ui.sessionTurn.diff.showMore": "Mostra più modifiche ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "{{count}} file modificato",
+  "ui.sessionTurn.diffs.changed.many": "{{count}} di file modificati",
   "ui.sessionTurn.diffs.changed.other": "{{count}} file modificati",
   "ui.sessionTurn.diffs.showAll": "Mostra tutto",
   "ui.sessionTurn.diffs.showLess": "Mostra meno",
@@ -95,10 +96,13 @@ export const dict: Record<string, string> = {
   "ui.messagePart.questions.dismissed": "Domande ignorate",
   "ui.messagePart.compaction": "Sessione compattata",
   "ui.messagePart.context.read.one": "{{count}} lettura",
+  "ui.messagePart.context.read.many": "{{count}} di letture",
   "ui.messagePart.context.read.other": "{{count}} letture",
   "ui.messagePart.context.search.one": "{{count}} ricerca",
+  "ui.messagePart.context.search.many": "{{count}} di ricerche",
   "ui.messagePart.context.search.other": "{{count}} ricerche",
   "ui.messagePart.context.list.one": "{{count}} elenco",
+  "ui.messagePart.context.list.many": "{{count}} di elenchi",
   "ui.messagePart.context.list.other": "{{count}} elenchi",
   "ui.list.loading": "Caricamento",
   "ui.list.empty": "Nessun risultato",

packages/ui/src/i18n/pl.ts

@@ -56,6 +56,8 @@ export const dict = {
   "ui.sessionTurn.summary.response": "Odpowiedź",
   "ui.sessionTurn.diff.showMore": "Pokaż więcej zmian ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "{{count}} zmieniony plik",
+  "ui.sessionTurn.diffs.changed.few": "{{count}} zmienione pliki",
+  "ui.sessionTurn.diffs.changed.many": "{{count}} zmienionych plików",
   "ui.sessionTurn.diffs.changed.other": "Liczba zmienionych plików: {{count}}",
   "ui.sessionTurn.diffs.showAll": "Pokaż wszystkie",
   "ui.sessionTurn.diffs.showLess": "Pokaż mniej",
@@ -94,10 +96,16 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "Pytania odrzucone",
   "ui.messagePart.compaction": "Sesja skompaktowana",
   "ui.messagePart.context.read.one": "Liczba odczytów: {{count}}",
+  "ui.messagePart.context.read.few": "Liczba odczytów: {{count}}",
+  "ui.messagePart.context.read.many": "Liczba odczytów: {{count}}",
   "ui.messagePart.context.read.other": "Liczba odczytów: {{count}}",
   "ui.messagePart.context.search.one": "Liczba wyszukiwań: {{count}}",
+  "ui.messagePart.context.search.few": "Liczba wyszukiwań: {{count}}",
+  "ui.messagePart.context.search.many": "Liczba wyszukiwań: {{count}}",
   "ui.messagePart.context.search.other": "Liczba wyszukiwań: {{count}}",
   "ui.messagePart.context.list.one": "Liczba list: {{count}}",
+  "ui.messagePart.context.list.few": "Liczba list: {{count}}",
+  "ui.messagePart.context.list.many": "Liczba list: {{count}}",
   "ui.messagePart.context.list.other": "Liczba list: {{count}}",
   "ui.messagePart.diagnostic.error": "Błąd",
   "ui.messagePart.title.edit": "Edycja",

packages/ui/src/i18n/ru.ts

@@ -56,6 +56,8 @@ export const dict = {
   "ui.sessionTurn.summary.response": "Ответ",
   "ui.sessionTurn.diff.showMore": "Показать ещё изменений ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "Изменённый файл: {{count}}",
+  "ui.sessionTurn.diffs.changed.few": "{{count}} изменённых файла",
+  "ui.sessionTurn.diffs.changed.many": "{{count}} изменённых файлов",
   "ui.sessionTurn.diffs.changed.other": "Изменённые файлы: {{count}}",
   "ui.sessionTurn.diffs.showAll": "Показать все",
   "ui.sessionTurn.diffs.showLess": "Показать меньше",
@@ -94,10 +96,16 @@ export const dict = {
   "ui.messagePart.questions.dismissed": "Вопросы отклонены",
   "ui.messagePart.compaction": "Сессия сжата",
   "ui.messagePart.context.read.one": "{{count}} чтение",
+  "ui.messagePart.context.read.few": "{{count}} чтения",
+  "ui.messagePart.context.read.many": "{{count}} чтений",
   "ui.messagePart.context.read.other": "Операций чтения: {{count}}",
   "ui.messagePart.context.search.one": "{{count}} поиск",
+  "ui.messagePart.context.search.few": "{{count}} поиска",
+  "ui.messagePart.context.search.many": "{{count}} поисков",
   "ui.messagePart.context.search.other": "Операций поиска: {{count}}",
   "ui.messagePart.context.list.one": "{{count}} список",
+  "ui.messagePart.context.list.few": "{{count}} списка",
+  "ui.messagePart.context.list.many": "{{count}} списков",
   "ui.messagePart.context.list.other": "Получено списков: {{count}}",
   "ui.messagePart.diagnostic.error": "Ошибка",
   "ui.messagePart.title.edit": "Редактировать",

packages/ui/src/i18n/uk.ts

@@ -59,6 +59,8 @@ export const dict: Record<string, string> = {
   "ui.sessionTurn.summary.response": "Відповідь",
   "ui.sessionTurn.diff.showMore": "Показати більше змін ({{count}})",
   "ui.sessionTurn.diffs.changed.one": "Змінений файл: {{count}}",
+  "ui.sessionTurn.diffs.changed.few": "Змінені файли: {{count}}",
+  "ui.sessionTurn.diffs.changed.many": "Змінених файлів: {{count}}",
   "ui.sessionTurn.diffs.changed.other": "Змінені файли: {{count}}",
   "ui.sessionTurn.diffs.showAll": "Показати всі",
   "ui.sessionTurn.diffs.showLess": "Показати менше",
@@ -102,10 +104,16 @@ export const dict: Record<string, string> = {
   "ui.messagePart.questions.dismissed": "Запитання відхилено",
   "ui.messagePart.compaction": "Сесію стиснуто",
   "ui.messagePart.context.read.one": "{{count}} читання",
+  "ui.messagePart.context.read.few": "{{count}} читання",
+  "ui.messagePart.context.read.many": "{{count}} читань",
   "ui.messagePart.context.read.other": "{{count}} читань",
   "ui.messagePart.context.search.one": "{{count}} пошук",
+  "ui.messagePart.context.search.few": "{{count}} пошуки",
+  "ui.messagePart.context.search.many": "{{count}} пошуків",
   "ui.messagePart.context.search.other": "{{count}} пошуків",
   "ui.messagePart.context.list.one": "{{count}} список",
+  "ui.messagePart.context.list.few": "{{count}} списки",
+  "ui.messagePart.context.list.many": "{{count}} списків",
   "ui.messagePart.context.list.other": "{{count}} списків",
 
   "ui.list.loading": "Завантаження",