fix(i18n): 繁体、港台和不带地区的中文浏览器都显示中文界面

panel/src/i18n/index.ts

@@ -1,4 +1,4 @@
-import i18next from "i18next";
+import i18next, { type InitOptions } from "i18next";
 import { initReactI18next } from "react-i18next";
 import LanguageDetector from "i18next-browser-languagedetector";
 import enCommon from "./resources/en-US/common.json";
@@ -25,11 +25,10 @@ import zhNavigation from "./resources/zh-CN/navigation.json";
 import zhBackups from "./resources/zh-CN/backups.json";
 import zhSubmissions from "./resources/zh-CN/submissions.json";
 import zhFiles from "./resources/zh-CN/files.json";
+import { panelLanguage, SUPPORTED_LANGUAGES } from "./language";
 
-i18next
-  .use(LanguageDetector)
-  .use(initReactI18next)
-  .init({
+// Exported so a test can boot a fresh instance with the same detection.
+export const i18nOptions: InitOptions = {
   resources: {
     "en-US": {
       common: enCommon,
@@ -60,6 +59,7 @@ i18next
       files: zhFiles,
     },
   },
+  supportedLngs: [...SUPPORTED_LANGUAGES],
   fallbackLng: "en-US",
   defaultNS: "common",
   interpolation: {
@@ -69,7 +69,10 @@ i18next
     order: ["localStorage", "navigator"],
     caches: ["localStorage"],
     lookupLocalStorage: "felis-lang",
+    convertDetectedLanguage: panelLanguage,
   },
-  });
+};
+
+i18next.use(LanguageDetector).use(initReactI18next).init(i18nOptions);
 
 export default i18next;

panel/src/i18n/language.test.ts

@@ -0,0 +1,71 @@
+// @vitest-environment jsdom
+import { describe, it, expect, vi, afterEach } from "vitest";
+import i18next from "i18next";
+import LanguageDetector from "i18next-browser-languagedetector";
+import { i18nOptions } from "./index";
+import { panelLanguage } from "./language";
+
+// boot starts a fresh instance with the panel's own options, as a first visit
+// with these browser languages (and whatever is in storage) would.
+async function boot(languages: string[]) {
+  vi.spyOn(window.navigator, "languages", "get").mockReturnValue(languages);
+  vi.spyOn(window.navigator, "language", "get").mockReturnValue(languages[0] ?? "");
+  const instance = i18next.createInstance().use(LanguageDetector);
+  await instance.init(i18nOptions);
+  return instance;
+}
+
+afterEach(() => {
+  vi.restoreAllMocks();
+});
+
+describe("the panel language on a first visit", () => {
+  it.each([
+    [["zh-CN"]],
+    [["zh-TW"]],
+    [["zh-HK", "en"]],
+    [["zh"]],
+    [["zh-Hant-TW"]],
+    // English listed after Chinese must not win.
+    [["zh-TW", "en-US", "en"]],
+    [["zh", "en-US"]],
+  ])("reads Chinese for a browser asking %j", async (languages) => {
+    const i18n = await boot(languages);
+
+    expect(i18n.language).toBe("zh-CN");
+    expect(i18n.t("common:loading")).toBe(i18n.getFixedT("zh-CN")("common:loading"));
+    expect(localStorage.getItem("felis-lang")).toBe("zh-CN");
+  });
+
+  it.each([[["en-GB"]], [["en-US", "zh-CN"]], [["fr-FR", "de"]], [[]]])(
+    "reads English for a browser asking %j",
+    async (languages) => {
+      const i18n = await boot(languages);
+
+      expect(i18n.language).toBe("en-US");
+    },
+  );
+
+  it("keeps a language chosen here over the browser's", async () => {
+    localStorage.setItem("felis-lang", "en-US");
+    const i18n = await boot(["zh-CN"]);
+
+    expect(i18n.language).toBe("en-US");
+  });
+
+  it("maps a regional code a past visit stored onto the shipped text", async () => {
+    localStorage.setItem("felis-lang", "zh-TW");
+    const i18n = await boot(["en-US"]);
+
+    expect(i18n.language).toBe("zh-CN");
+  });
+});
+
+describe("panelLanguage", () => {
+  it("maps any Chinese or English code onto a shipped translation", () => {
+    expect(panelLanguage("zh_TW")).toBe("zh-CN");
+    expect(panelLanguage("ZH-hk")).toBe("zh-CN");
+    expect(panelLanguage("en")).toBe("en-US");
+    expect(panelLanguage("ja-JP")).toBe("ja-JP");
+  });
+});

panel/src/i18n/language.ts

@@ -0,0 +1,17 @@
+// The panel ships two translations; everything a browser reports is mapped onto
+// one of them before i18next picks. Any Chinese (zh, zh-TW, zh-HK, zh-Hant, a
+// stale "zh_TW" in storage) reads the zh-CN text and any English the en-US
+// text. Mapping at detection matters: i18next first looks for an exact
+// supported code anywhere in the browser's list, so ["zh-TW", "en-US"] would
+// land on English if zh-TW reached it unmapped.
+
+export const SUPPORTED_LANGUAGES = ["en-US", "zh-CN"] as const;
+
+/** panelLanguage maps a detected language code onto a shipped translation, or
+ *  returns it unchanged for i18next to pass over. */
+export function panelLanguage(code: string): string {
+  const base = code.trim().toLowerCase().split(/[-_]/)[0];
+  if (base === "zh") return "zh-CN";
+  if (base === "en") return "en-US";
+  return code;
+}

panel/vite.config.ts

@@ -38,7 +38,7 @@ export default defineConfig(async ({ mode }) => {
       },
     },
     test: {
-      setupFiles: ["./vitest.setup.ts"],
+      setupFiles: ["./vitest.storage.ts", "./vitest.setup.ts"],
       // e2e/*.spec.ts belong to Playwright (npm run test:e2e).
       include: ["src/**/*.test.{ts,tsx}"],
     },

panel/vitest.storage.ts

@@ -0,0 +1,38 @@
+import { beforeEach } from "vitest";
+
+// Node 26 puts its own localStorage on globalThis, undefined unless node runs
+// with --localstorage-file, and it shadows jsdom's. Component tests get an
+// in-memory one so code that remembers things (the language, console history)
+// runs as in a browser. This file runs before the i18n boot in vitest.setup.ts,
+// because the language detector decides once whether storage works.
+class MemoryStorage implements Storage {
+  #data = new Map<string, string>();
+  get length() {
+    return this.#data.size;
+  }
+  key(index: number) {
+    return [...this.#data.keys()][index] ?? null;
+  }
+  getItem(key: string) {
+    return this.#data.get(key) ?? null;
+  }
+  setItem(key: string, value: string) {
+    this.#data.set(key, String(value));
+  }
+  removeItem(key: string) {
+    this.#data.delete(key);
+  }
+  clear() {
+    this.#data.clear();
+  }
+}
+
+if (typeof window !== "undefined" && !globalThis.localStorage) {
+  Object.defineProperty(globalThis, "localStorage", {
+    value: new MemoryStorage(),
+    configurable: true,
+    writable: true,
+  });
+  // Each test starts empty, including of the boot's own cached language.
+  beforeEach(() => localStorage.clear());
+}