Match multiple locales for spellchecker

ACKNOWLEDGMENTS.md

@@ -9,6 +9,10 @@ Signal Desktop makes use of the following open source projects.
 
     License: MIT
 
+## @formatjs/intl-localematcher
+
+    License: MIT
+
 ## @indutny/frameless-titlebar
 
     MIT License

app/main.ts

@@ -800,7 +800,11 @@ async function createWindow() {
   }
 
   mainWindowCreated = true;
-  setupSpellChecker(mainWindow, getResolvedMessagesLocale());
+  setupSpellChecker(
+    mainWindow,
+    getPreferredSystemLocales(),
+    getResolvedMessagesLocale().i18n
+  );
   if (!startInTray && windowConfig && windowConfig.maximized) {
     mainWindow.maximize();
   }

app/spell_check.ts

@@ -3,44 +3,62 @@
 
 import type { BrowserWindow } from 'electron';
 import { Menu, clipboard, nativeImage } from 'electron';
-import { uniq } from 'lodash';
 import { fileURLToPath } from 'url';
+import * as LocaleMatcher from '@formatjs/intl-localematcher';
 
 import { maybeParseUrl } from '../ts/util/url';
-import type { LocaleType } from './locale';
 
 import type { MenuListType } from '../ts/types/menu';
+import type { LocalizerType } from '../ts/types/Util';
 
 export function getLanguages(
-  userLocale: string,
-  availableLocales: ReadonlyArray<string>
+  preferredSystemLocales: ReadonlyArray<string>,
+  availableLocales: ReadonlyArray<string>,
+  defaultLocale: string
 ): Array<string> {
-  // First attempt to find the exact locale
-  const candidateLocales = uniq([userLocale, userLocale]).filter(l =>
-    availableLocales.includes(l)
-  );
-  if (candidateLocales.length > 0) {
-    return candidateLocales;
+  const matchedLocales = [];
+
+  preferredSystemLocales.forEach(preferredSystemLocale => {
+    if (preferredSystemLocale === defaultLocale) {
+      matchedLocales.push(defaultLocale);
+      return;
+    }
+    const matchedLocale = LocaleMatcher.match(
+      [preferredSystemLocale],
+      availableLocales as Array<string>, // bad types
+      defaultLocale,
+      { algorithm: 'best fit' }
+    );
+    if (matchedLocale !== defaultLocale) {
+      matchedLocales.push(matchedLocale);
+    }
+  });
+
+  if (matchedLocales.length === 0) {
+    matchedLocales.push(defaultLocale);
   }
 
-  // If no languages were found then return all locales that start with the base
-  const baseLocale = userLocale.split('-')[0];
-  return uniq(availableLocales.filter(l => l.startsWith(baseLocale)));
+  return matchedLocales;
 }
 
 export const setup = (
   browserWindow: BrowserWindow,
-  { name: userLocale, i18n }: LocaleType
+  preferredSystemLocales: ReadonlyArray<string>,
+  i18n: LocalizerType
 ): void => {
   const { session } = browserWindow.webContents;
   const availableLocales = session.availableSpellCheckerLanguages;
-  const languages = getLanguages(userLocale, availableLocales);
-  console.log(`spellcheck: user locale: ${userLocale}`);
+  const languages = getLanguages(
+    preferredSystemLocales,
+    availableLocales,
+    'en'
+  );
+  console.log('spellcheck: user locales:', preferredSystemLocales);
   console.log(
-    'spellcheck: available spellchecker languages: ',
+    'spellcheck: available spellchecker languages:',
     availableLocales
   );
-  console.log('spellcheck: setting languages to: ', languages);
+  console.log('spellcheck: setting languages to:', languages);
   session.setSpellCheckerLanguages(languages);
 
   browserWindow.webContents.on('context-menu', (_event, params) => {

package.json

@@ -80,6 +80,7 @@
   },
   "dependencies": {
     "@formatjs/fast-memoize": "1.2.6",
+    "@formatjs/intl-localematcher": "0.2.32",
     "@indutny/frameless-titlebar": "2.3.5",
     "@indutny/sneequals": "4.0.0",
     "@popperjs/core": "2.11.6",

ts/test-node/app/spell_check_test.ts

@@ -8,34 +8,48 @@ import { getLanguages } from '../../../app/spell_check';
 describe('SpellCheck', () => {
   describe('getLanguages', () => {
     it('works with locale and base available', () => {
-      assert.deepEqual(getLanguages('en-US', ['en-US', 'en-CA', 'en']), [
+      assert.deepEqual(getLanguages(['en-US'], ['en-US', 'en'], 'en'), [
         'en-US',
       ]);
     });
 
-    it('works with neither locale nor base available', () => {
-      assert.deepEqual(getLanguages('en-US', ['en-NZ', 'en-CA']), [
-        'en-NZ',
-        'en-CA',
+    it('uses icu likely subtags rules to match languages', () => {
+      assert.deepEqual(getLanguages(['fa-FR'], ['fa-IR'], 'en'), ['fa-IR']);
+      assert.deepEqual(getLanguages(['zh'], ['zh-Hans-CN'], 'en'), [
+        'zh-Hans-CN',
       ]);
+      assert.deepEqual(
+        getLanguages(['zh-HK'], ['zh-Hans-CN', 'zh-Hant-HK'], 'en'),
+        ['zh-Hant-HK']
+      );
+    });
+
+    it('matches multiple locales', () => {
+      assert.deepEqual(
+        getLanguages(['fr-FR', 'es'], ['fr', 'es-ES', 'en-US'], 'en'),
+        ['fr', 'es-ES']
+      );
     });
 
     it('works with only base locale available', () => {
-      assert.deepEqual(getLanguages('en-US', ['en', 'en-CA']), ['en', 'en-CA']);
+      assert.deepEqual(getLanguages(['en-US'], ['en'], 'en'), ['en']);
     });
 
     it('works with only full locale available', () => {
-      assert.deepEqual(getLanguages('en-US', ['en-CA', 'en-US']), ['en-US']);
+      assert.deepEqual(getLanguages(['en-US'], ['en-CA', 'en-US'], 'en'), [
+        'en-US',
+      ]);
     });
 
     it('works with base provided and base available', () => {
-      assert.deepEqual(getLanguages('en', ['en-CA', 'en-US', 'en']), ['en']);
+      assert.deepEqual(getLanguages(['en'], ['en-CA', 'en-US', 'en'], 'en'), [
+        'en',
+      ]);
     });
 
-    it('works with base provided and base not available', () => {
-      assert.deepEqual(getLanguages('en', ['en-CA', 'en-US']), [
-        'en-CA',
-        'en-US',
+    it('falls back to default', () => {
+      assert.deepEqual(getLanguages(['fa-IR'], ['es-ES', 'fr-FR'], 'en'), [
+        'en',
       ]);
     });
   });