i18n: add Traditional Chinese (zh-TW)

Add a complete Taiwan Traditional Chinese catalog, locale selection,
Chinese readout formatting, translation notes and regression coverage.
Seed translations from #724 and #652 and adapt the zh-CN catalog.

Co-authored-by: caxer <[email protected]>
Co-authored-by: tbdavid2019 <[email protected]>
Co-authored-by: Enzo Abyie <[email protected]>
Co-authored-by: EDIT-Aeterna <[email protected]>

src/hudLocalityFormat.js

@@ -16,7 +16,8 @@ export function hudQuantity(value, unit, digits = 0) {
     maximumFractionDigits: digits,
   });
   const label = unitLabel(unit);
-  if (getLocale() === 'zh-CN') return label ? `${number} ${label}` : number;
+  if (getLocale().startsWith('zh-'))
+    return label ? `${number} ${label}` : number;
   return `${number}${label.toUpperCase()}`;
 }
 

src/i18n/firms-live-zh.test.mjs

@@ -5,12 +5,12 @@ import { createModel } from '../layers/firms/model.js';
 import { createQueries } from '../layers/firms/queries.js';
 
 const cases = [
-  [0, '不到 1 分钟前', '<1m ago'],
-  [120000, '2 分钟前', '2m ago'],
-  [7200000, '2 小时前', '2h ago'],
+  [0, '不到 1 分钟前', '<1m ago', '不到 1 分鐘前'],
+  [120000, '2 分钟前', '2m ago', '2 分鐘前'],
+  [7200000, '2 小时前', '2h ago', '2 小時前'],
 ];
 
-for (const [age, zh, en] of cases) {
+for (const [age, zh, en, tw] of cases) {
   test(`FIRMS live age ${age} ms has one relative-time suffix`, (context) => {
     const now = 1800000000000;
     context.mock.method(Date, 'now', () => now);
@@ -36,6 +36,8 @@ for (const [age, zh, en] of cases) {
       assert.equal(methods.getStats().loadingLabel, `LIVE · updated ${en}`);
       setLocale('zh-CN');
       assert.equal(methods.getStats().loadingLabel, `实时 · 更新于 ${zh}`);
+      setLocale('zh-TW');
+      assert.equal(methods.getStats().loadingLabel, `即時 · 更新於 ${tw}`);
     } finally {
       setLocale(previousLocale);
     }

src/i18n/i18n.test.mjs

@@ -35,12 +35,16 @@ test('normalizeLocale folds regional variants and rejects unshipped tags', () =>
   assert.equal(normalizeLocale(' RU '), 'ru');
   assert.equal(normalizeLocale('en_GB'), 'en');
   assert.equal(normalizeLocale('xx'), null);
-  // Simplified Chinese by default; Traditional tags wait for zh-TW.
+  // Explicit script tags take precedence over regional defaults.
   assert.equal(normalizeLocale('zh'), 'zh-CN');
   assert.equal(normalizeLocale('zh-CN'), 'zh-CN');
   assert.equal(normalizeLocale('zh-Hans-SG'), 'zh-CN');
-  assert.equal(normalizeLocale('zh-TW'), null);
-  assert.equal(normalizeLocale('zh-Hant-HK'), null);
+  assert.equal(normalizeLocale('zh-TW'), 'zh-TW');
+  assert.equal(normalizeLocale('zh-Hant-HK'), 'zh-TW');
+  assert.equal(normalizeLocale('zh-Hans-TW'), 'zh-CN');
+  assert.equal(normalizeLocale('zh-Hant-CN'), 'zh-TW');
+  assert.equal(normalizeLocale('zh_HK'), 'zh-TW');
+  assert.equal(normalizeLocale('zh-MO'), 'zh-TW');
   assert.equal(normalizeLocale(undefined), null);
 });
 

src/i18n/index.js

@@ -19,8 +19,9 @@ import {
 import es from './locales/es.json' with { type: 'json' };
 import ru from './locales/ru.json' with { type: 'json' };
 import zhCN from './locales/zh-CN.json' with { type: 'json' };
+import zhTW from './locales/zh-TW.json' with { type: 'json' };
 
-const CATALOGS = Object.freeze({ es, ru, 'zh-CN': zhCN });
+const CATALOGS = Object.freeze({ es, ru, 'zh-CN': zhCN, 'zh-TW': zhTW });
 
 let currentLocale = DEFAULT_LOCALE;
 

src/i18n/locale.js

@@ -8,7 +8,7 @@ export const LOCALE_STORAGE_KEY = 'gev:locale:v1';
 export const DEFAULT_LOCALE = 'en';
 
 /** Shipped locales; order does not matter. Adding one: docs/TRANSLATORS.md. */
-export const LOCALES = Object.freeze(['en', 'es', 'ru', 'zh-CN']);
+export const LOCALES = Object.freeze(['en', 'es', 'ru', 'zh-CN', 'zh-TW']);
 
 /** Each locale named in its own language, for the selector. */
 export const LOCALE_NAMES = Object.freeze({
@@ -16,6 +16,7 @@ export const LOCALE_NAMES = Object.freeze({
   es: 'Español',
   ru: 'Русский',
   'zh-CN': '简体中文',
+  'zh-TW': '繁體中文',
 });
 
 /** Right-to-left locales. */
@@ -29,11 +30,12 @@ const RTL_LOCALES = Object.freeze([]);
 export function normalizeLocale(candidate) {
   if (typeof candidate !== 'string') return null;
   const [primary, ...rest] = candidate.trim().toLowerCase().split(/[-_]/);
-  // Traditional Chinese readers are not given Simplified: no zh-TW yet.
-  if (primary === 'zh')
+  if (primary === 'zh') {
+    if (rest.includes('hans')) return 'zh-CN';
     return rest.some((part) => ['hant', 'tw', 'hk', 'mo'].includes(part))
-      ? null
+      ? 'zh-TW'
       : 'zh-CN';
+  }
   return LOCALES.includes(primary) ? primary : null;
 }
 

src/i18n/same-as-english.json

@@ -192,5 +192,60 @@
     "ΔE",
     "ΔN",
     "▲ {frp} MW"
+  ],
+  "zh-TW": [
+    "1090 MHz",
+    "978 MHz UAT",
+    "AIS: --",
+    "AIS: {name}",
+    "BRG {value}°",
+    "BRG —",
+    "CAL {value}",
+    "CAL · {badge}",
+    "CCTV",
+    "CRS {value}°",
+    "CRT",
+    "FLIR",
+    "FOV",
+    "FOV {value}°",
+    "FT",
+    "GEO",
+    "HDG",
+    "HDG {value}°",
+    "House",
+    "Ironbow",
+    "KTS",
+    "Landsat 8/9",
+    "MM",
+    "NVG",
+    "REC",
+    "SRC {value}",
+    "Sentinel-2",
+    "Techno",
+    "Trance",
+    "USB {rate} msg/s",
+    "WHOT/BHOT",
+    "dB",
+    "ft",
+    "hPa",
+    "hemisphere|E",
+    "hemisphere|N",
+    "hemisphere|S",
+    "hemisphere|W",
+    "km",
+    "km/h",
+    "kt",
+    "kts",
+    "mph",
+    "{city} CCTV",
+    "{rate} msg/s",
+    "{source} HTTP {status}",
+    "{speed} kn",
+    "{type}  SPD: {speed}  HDG: {heading}",
+    "{value} KM",
+    "{value} KM/S",
+    "ΔE",
+    "ΔN",
+    "▲ {frp} MW"
   ]
 }

src/i18n/zh-TW-display.test.mjs

@@ -0,0 +1,60 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { setLocale, t, tn, getLocale } from './index.js';
+import { resolveLocale, LOCALE_STORAGE_KEY } from './locale.js';
+import { hudQuantity, LOCALIZED_LOCALITY } from '../hudLocalityFormat.js';
+import { formatCockpitDistance } from '../ui/cockpitPresentation.js';
+import { READOUT_WORDS } from '../layers/recentImagery/display.js';
+import { cctvSourceStatusLabel } from '../ui/cctvFrames.js';
+
+test('Traditional Chinese resolves from URL, saved preference and browser language', () => {
+  assert.equal(
+    resolveLocale({
+      location: { search: '?lang=zh-TW' },
+      storage: { getItem: () => 'en' },
+      languages: ['en'],
+    }),
+    'zh-TW',
+  );
+  assert.equal(
+    resolveLocale({
+      location: { search: '' },
+      storage: {
+        getItem: (key) => (key === LOCALE_STORAGE_KEY ? 'zh-TW' : null),
+      },
+      languages: ['en'],
+    }),
+    'zh-TW',
+  );
+  assert.equal(
+    resolveLocale({
+      location: { search: '' },
+      storage: { getItem: () => null },
+      languages: ['zh-Hant', 'en'],
+    }),
+    'zh-TW',
+  );
+});
+
+test('Traditional Chinese readouts preserve unit case, coordinates and natural relative dates', () => {
+  const previous = getLocale();
+  try {
+    setLocale('zh-TW');
+    assert.equal(hudQuantity(2069, 'km', 1), '2069.0 km');
+    assert.equal(formatCockpitDistance(14000), '14\u00a0km');
+    assert.equal(
+      LOCALIZED_LOCALITY.sector({ latDeg: 21.33, lonDeg: -77.5 }),
+      '扇區 21.33N 77.50W',
+    );
+    assert.equal(READOUT_WORDS.daysAgo(9), '9 天前');
+    assert.equal(READOUT_WORDS.daysAgo(0), '今天');
+    assert.equal(cctvSourceStatusLabel('ok'), '正常');
+    assert.equal(t('SAVE KEYS'), '儲存金鑰');
+    assert.equal(
+      tn(2, 'Click {count} more point.', 'Click {count} more points.'),
+      '再點選 2 個點。',
+    );
+  } finally {
+    setLocale(previous);
+  }
+});

src/layers/recentImagery/display.js

@@ -33,7 +33,9 @@ export const READOUT_WORDS = Object.freeze({
   date: (day) => displayDay(day, LONG_DAY),
   daysAgo: (delta) => {
     const text = formatRelativeTime(delta > 0 ? -delta : 0, 'day');
-    return getLocale() === 'zh-CN' ? text.replace(/(\d)(?=天)/g, '$1 ') : text;
+    return getLocale().startsWith('zh-')
+      ? text.replace(/(\d)(?=天)/g, '$1 ')
+      : text;
   },
   // "Sentinel-2" never breaks at its hyphen: a word joiner follows it
   // (JetBrains Mono has no U+2011 non-breaking hyphen).

src/ui/cockpitContext.js

@@ -15,7 +15,7 @@ const LOCALIZED_CONTEXT_SCOPE = Object.freeze({
   window: ({ label, radiusKm }) =>
     t('{label} · {radius} AIR/SEA WINDOW', {
       label,
-      radius: `${radiusKm === null ? '—' : formatNumber(radiusKm)}\u00a0${getLocale() === 'zh-CN' ? unitLabel('km') : unitLabel('km').toUpperCase()}`,
+      radius: `${radiusKm === null ? '—' : formatNumber(radiusKm)}\u00a0${getLocale().startsWith('zh-') ? unitLabel('km') : unitLabel('km').toUpperCase()}`,
     }),
   installations: ({ scope, coverage }) =>
     t('{scope} · INSTALLATIONS {coverage}', { scope, coverage }),

src/ui/cockpitPresentation.js

@@ -149,7 +149,7 @@ export function formatCockpitDistance(distanceM) {
     minimumFractionDigits: digits,
     maximumFractionDigits: digits,
   });
-  return getLocale() === 'zh-CN' ? distance : distance.toUpperCase();
+  return getLocale().startsWith('zh-') ? distance : distance.toUpperCase();
 }
 
 export function formatCockpitWindDirection(value) {

src/ui/localePicker.test.mjs

@@ -40,7 +40,7 @@ test('the current language comes first, the rest by their own names', () => {
         nativeNames: LOCALE_NAMES,
       }),
     ),
-    ['ru', 'en', 'es', 'zh-CN'],
+    ['ru', 'en', 'es', 'zh-CN', 'zh-TW'],
   );
   assert.deepEqual(
     codes(
@@ -50,7 +50,7 @@ test('the current language comes first, the rest by their own names', () => {
         nativeNames: LOCALE_NAMES,
       }),
     ),
-    ['es', 'en', 'ru', 'zh-CN'],
+    ['es', 'en', 'ru', 'zh-CN', 'zh-TW'],
   );
   assert.deepEqual(
     codes(
@@ -60,7 +60,7 @@ test('the current language comes first, the rest by their own names', () => {
         nativeNames: LOCALE_NAMES,
       }),
     ),
-    ['en', 'es', 'ru', 'zh-CN'],
+    ['en', 'es', 'ru', 'zh-CN', 'zh-TW'],
   );
   const rows = buildLocaleOptions({
     locales: MANY,
@@ -263,7 +263,7 @@ test('keyboard model: open on the current language, move, choose, close', () =>
   assert.deepEqual(model.keydown({ key: 'ArrowDown' }), { handled: true });
   assert.equal(model.activeOption.code, 'en');
   model.keydown({ key: 'End' });
-  assert.equal(model.activeOption.code, 'zh-CN');
+  assert.equal(model.activeOption.code, 'zh-TW');
   model.keydown({ key: 'Home' });
   assert.equal(model.activeOption.code, 'ru');
   model.keydown({ key: 'ArrowUp' });