fix: Unsupported language is automatically added to preload option #2178

i18next · Apr 29, 2024 · c1e2f91 · c1e2f91
1 parent c9e2bf5
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 23.11.3
+
+- fix: Unsupported language is automatically added to preload option [2178](https://github.com/i18next/i18next/issues/2178)
+
 ## 23.11.2
 
 - allow defaultValue in nested translation [2174](https://github.com/i18next/i18next/issues/2174)

diff --git a/src/i18next.js b/src/i18next.js
@@ -490,7 +490,7 @@ class I18n extends EventEmitter {
     if (typeof lngs === 'string') lngs = [lngs];
     const preloaded = this.options.preload || [];
 
-    const newLngs = lngs.filter(lng => preloaded.indexOf(lng) < 0);
+    const newLngs = lngs.filter(lng => preloaded.indexOf(lng) < 0 && this.services.languageUtils.isSupportedCode(lng));
     // Exit early if all given languages are already preloaded
     if (!newLngs.length) {
       if (callback) callback();

diff --git a/test/runtime/i18next.test.js b/test/runtime/i18next.test.js
@@ -338,4 +338,59 @@ describe('i18next', () => {
       });
     });
   });
+
+  describe('#loadLanguages()', () => {
+    describe('with supportedLngs', () => {
+      /** @type {import('i18next').i18n} */
+      let newInstance;
+      beforeAll(async () => {
+        newInstance = i18next.createInstance({
+          fallbackLng: 'en',
+          supportedLngs: ['en', 'de', 'it'],
+          preload: ['en', 'de'],
+        });
+        await newInstance.init();
+      });
+
+      describe('passing a supported lng', () => {
+        it('it should extend preload', () => {
+          newInstance.loadLanguages('it');
+          expect(newInstance.options.preload).to.include('it');
+        });
+      });
+
+      describe('passing a non supported lng', () => {
+        it('it should extend preload', () => {
+          newInstance.loadLanguages('es');
+          expect(newInstance.options.preload).not.to.include('es');
+        });
+      });
+    });
+
+    describe('without supportedLngs', () => {
+      /** @type {import('i18next').i18n} */
+      let newInstance;
+      beforeAll(async () => {
+        newInstance = i18next.createInstance({
+          fallbackLng: 'en',
+          preload: ['en', 'de'],
+        });
+        await newInstance.init();
+      });
+
+      describe('passing a supported lng', () => {
+        it('it should extend preload', () => {
+          newInstance.loadLanguages('it');
+          expect(newInstance.options.preload).to.include('it');
+        });
+      });
+
+      describe('passing a non supported lng', () => {
+        it('it should extend preload', () => {
+          newInstance.loadLanguages('es');
+          expect(newInstance.options.preload).to.include('es');
+        });
+      });
+    });
+  });
 });