offer possibility to define a language detector detect function as pr…

…omise #1879
i18next · Dec 10, 2022 · 7e7c751 · 7e7c751
1 parent 2f4aea3
commit 7e7c751
Show file tree

Hide file tree

Showing 7 changed files with 182 additions and 13 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 22.3.0
+
+- offer possibility to define a language detector's detect function as promise
+
 ## 22.2.0
 
 - types: extend the init method with a generic parameter for backend options [1878](https://github.com/i18next/i18next/pull/1878), [105](https://github.com/i18next/i18next-http-backend/pull/105), [34](https://github.com/i18next/i18next-fs-backend/pull/34)

diff --git a/i18next.js b/i18next.js
@@ -2212,7 +2212,7 @@
           });
           if (this.modules.languageDetector) {
             s.languageDetector = createClassOnDemand(this.modules.languageDetector);
-            s.languageDetector.init(s, this.options.detection, this.options);
+            if (s.languageDetector.init) s.languageDetector.init(s, this.options.detection, this.options);
           }
           if (this.modules.i18nFormat) {
             s.i18nFormat = createClassOnDemand(this.modules.i18nFormat);
@@ -2405,7 +2405,7 @@
               setLngProps(l);
             }
             if (!_this4.translator.language) _this4.translator.changeLanguage(l);
-            if (_this4.services.languageDetector) _this4.services.languageDetector.cacheUserLanguage(l);
+            if (_this4.services.languageDetector && _this4.services.languageDetector.cacheUserLanguage) _this4.services.languageDetector.cacheUserLanguage(l);
           }
           _this4.loadResources(l, function (err) {
             done(err, l);
@@ -2414,7 +2414,11 @@
         if (!lng && this.services.languageDetector && !this.services.languageDetector.async) {
           setLng(this.services.languageDetector.detect());
         } else if (!lng && this.services.languageDetector && this.services.languageDetector.async) {
-          this.services.languageDetector.detect(setLng);
+          if (this.services.languageDetector.detect.length === 0) {
+            this.services.languageDetector.detect().then(setLng);
+          } else {
+            this.services.languageDetector.detect(setLng);
+          }
         } else {
           setLng(lng);
         }

diff --git a/i18next.min.js b/i18next.min.js
diff --git a/index.d.ts b/index.d.ts
@@ -1052,10 +1052,10 @@ export interface BackendModule<TOptions = object> extends Module {
  */
 export interface LanguageDetectorModule extends Module {
   type: 'languageDetector';
-  init(services: Services, detectorOptions: object, i18nextOptions: InitOptions): void;
+  init?(services: Services, detectorOptions: object, i18nextOptions: InitOptions): void;
   /** Must return detected language */
   detect(): string | readonly string[] | undefined;
-  cacheUserLanguage(lng: string): void;
+  cacheUserLanguage?(lng: string): void;
 }
 
 /**
@@ -1067,10 +1067,12 @@ export interface LanguageDetectorAsyncModule extends Module {
   type: 'languageDetector';
   /** Set to true to enable async detection */
   async: true;
-  init(services: Services, detectorOptions: object, i18nextOptions: InitOptions): void;
-  /** Must call callback passing detected language */
-  detect(callback: (lng: string | readonly string[] | undefined) => void): void;
-  cacheUserLanguage(lng: string): void;
+  init?(services: Services, detectorOptions: object, i18nextOptions: InitOptions): void;
+  /** Must call callback passing detected language or return a Promise*/
+  detect(
+    callback: (lng: string | readonly string[] | undefined) => void | undefined,
+  ): void | Promise<string | readonly string[] | undefined>;
+  cacheUserLanguage?(lng: string): void | Promise<void>;
 }
 
 /**

diff --git a/src/i18next.js b/src/i18next.js
@@ -136,7 +136,7 @@ class I18n extends EventEmitter {
 
       if (this.modules.languageDetector) {
         s.languageDetector = createClassOnDemand(this.modules.languageDetector);
-        s.languageDetector.init(s, this.options.detection, this.options);
+        if (s.languageDetector.init) s.languageDetector.init(s, this.options.detection, this.options);
       }
 
       if (this.modules.i18nFormat) {
@@ -355,7 +355,7 @@ class I18n extends EventEmitter {
         }
         if (!this.translator.language) this.translator.changeLanguage(l);
 
-        if (this.services.languageDetector) this.services.languageDetector.cacheUserLanguage(l);
+        if (this.services.languageDetector && this.services.languageDetector.cacheUserLanguage) this.services.languageDetector.cacheUserLanguage(l);
       }
 
       this.loadResources(l, err => {
@@ -366,7 +366,11 @@ class I18n extends EventEmitter {
     if (!lng && this.services.languageDetector && !this.services.languageDetector.async) {
       setLng(this.services.languageDetector.detect());
     } else if (!lng && this.services.languageDetector && this.services.languageDetector.async) {
-      this.services.languageDetector.detect(setLng);
+      if (this.services.languageDetector.detect.length === 0) {
+        this.services.languageDetector.detect().then(setLng);
+      } else {
+        this.services.languageDetector.detect(setLng);
+      }
     } else {
       setLng(lng);
     }

diff --git a/test/languageDetector.spec.js b/test/languageDetector.spec.js
@@ -0,0 +1,119 @@
+import { createInstance } from '../src/index.js';
+import { expect } from 'chai';
+
+describe('LanguageDetector with different signatures', () => {
+  describe('LanguageDetector with minimal sync signature', () => {
+    let detectingLanguage = 'de-CH';
+    let i18n = createInstance();
+    i18n.use({
+      type: 'languageDetector',
+      detect: () => detectingLanguage,
+    });
+
+    describe('#init', () => {
+      it('should work as usual', () => {
+        i18n.init({ initImmediate: false });
+        expect(i18n.language).to.eql('de-CH');
+      });
+    });
+
+    describe('#changeLanguage', () => {
+      it('should detect the language accordingly', () => {
+        detectingLanguage = 'it';
+        i18n.changeLanguage();
+        expect(i18n.language).to.eql('it');
+      });
+    });
+  });
+
+  describe('LanguageDetector with full sync signature', () => {
+    let detectingLanguage = 'de-CH';
+    let cachedLng;
+    let i18n = createInstance();
+    i18n.use({
+      type: 'languageDetector',
+      init: () => {},
+      detect: () => detectingLanguage,
+      cacheUserLanguage: (l) => (cachedLng = l),
+    });
+
+    describe('#init', () => {
+      it('should work as usual', () => {
+        i18n.init({ initImmediate: false });
+        expect(i18n.language).to.eql('de-CH');
+        expect(cachedLng).to.eql('de-CH');
+      });
+    });
+
+    describe('#changeLanguage', () => {
+      it('should detect the language accordingly', () => {
+        detectingLanguage = 'it';
+        i18n.changeLanguage();
+        expect(i18n.language).to.eql('it');
+        expect(cachedLng).to.eql('it');
+      });
+    });
+  });
+
+  describe('LanguageDetector with async callback signature', () => {
+    let detectingLanguage = 'de-CH';
+    let i18n = createInstance();
+    i18n.use({
+      type: 'languageDetector',
+      async: true,
+      detect: (clb) => clb(detectingLanguage),
+    });
+
+    describe('#init', () => {
+      it('should work as usual', (done) => {
+        i18n.init({}, (err) => {
+          expect(i18n.language).to.eql('de-CH');
+          done(err);
+        });
+      });
+    });
+
+    describe('#changeLanguage', () => {
+      it('should detect the language accordingly', (done) => {
+        detectingLanguage = 'it';
+        i18n.changeLanguage(undefined, (err) => {
+          expect(i18n.language).to.eql('it');
+          done(err);
+        });
+      });
+    });
+  });
+
+  describe('LanguageDetector with async promise signature', () => {
+    let detectingLanguage = 'de-CH';
+    let cachedLng;
+    let i18n = createInstance();
+    i18n.use({
+      type: 'languageDetector',
+      async: true,
+      detect: async () => Promise.resolve(detectingLanguage),
+      cacheUserLanguage: async (l) => (cachedLng = l),
+    });
+
+    describe('#init', () => {
+      it('should work as usual', (done) => {
+        i18n.init({}, (err) => {
+          expect(i18n.language).to.eql('de-CH');
+          expect(cachedLng).to.eql('de-CH');
+          done(err);
+        });
+      });
+    });
+
+    describe('#changeLanguage', () => {
+      it('should detect the language accordingly', (done) => {
+        detectingLanguage = 'it';
+        i18n.changeLanguage(undefined, (err) => {
+          expect(i18n.language).to.eql('it');
+          expect(cachedLng).to.eql('it');
+          done(err);
+        });
+      });
+    });
+  });
+});
diff --git a/test/typescript/languageDetector.test.ts b/test/typescript/languageDetector.test.ts
@@ -0,0 +1,36 @@
+import { createInstance, LanguageDetectorAsyncModule, LanguageDetectorModule } from 'i18next';
+
+let i18n = createInstance();
+i18n
+  .use<LanguageDetectorModule>({
+    type: 'languageDetector',
+    detect: () => 'en',
+  })
+  .init();
+
+i18n = createInstance();
+i18n
+  .use<LanguageDetectorAsyncModule>({
+    type: 'languageDetector',
+    async: true,
+    detect: (clb) => clb('en'),
+  })
+  .init();
+
+i18n = createInstance();
+i18n
+  .use<LanguageDetectorAsyncModule>({
+    type: 'languageDetector',
+    async: true,
+    detect: async () => 'en',
+  })
+  .init();
+
+i18n = createInstance();
+i18n
+  .use({
+    type: 'languageDetector',
+    async: true,
+    detect: (clb: (lng: string) => void) => clb('en'),
+  })
+  .init();