feat: Bind i18n and resource store events to clear the memoized cache

README.md

@@ -76,7 +76,13 @@ i18next
   memoizeFallback: false,
 
   // array or single object of loaded 'i18next-icu/locale-data
-  localeData: null
+  localeData: null,
+
+  // which events should clear the cache, can be set to false or string of events separated by " "
+  bindI18n: '',
+
+  // which events on resourceSource should clear the cache, can be set to false or string of events separated by " "
+  bindI18nStore: ''
 }
 ```
 

index.d.ts

@@ -27,12 +27,15 @@ declare module "i18next-icu" {
     memoizeFallback?: boolean;
     localeData?: LocaleData | LocaleData[];
     formats?: IcuFormats;
+    bindI18n?: string;
+    bindI18nStore?: string;
   }
 
   export interface IcuInstance extends ThirdPartyModule {
     init(i18next: i18n, options?: IcuConfig): void;
     addLocaleData(localeData: LocaleData | LocaleData[]): void;
     addUserDefinedFormats(formats: IcuFormats): void;
+    clearCache(): void;
   }
 
   interface IcuConstructor {

src/index.js

@@ -4,7 +4,9 @@ import IntlMessageFormat from 'intl-messageformat';
 function getDefaults() {
   return {
     memoize: true,
-    memoizeFallback: false
+    memoizeFallback: false,
+    bindI18n: '',
+    bindI18nStore: '',
   };
 }
 
@@ -22,8 +24,20 @@ class ICU {
     this.formats = this.options.formats;
 
     if (i18next) {
+      const { bindI18n, bindI18nStore, memoize } = this.options; 
+
       i18next.IntlMessageFormat = IntlMessageFormat;
       i18next.ICU = this;
+
+      if (memoize) {
+        if (bindI18n) {
+          i18next.on(bindI18n, () => this.clearCache())
+        }
+
+        if (bindI18nStore) {
+          i18next.store.on(bindI18nStore, () => this.clearCache())
+        }
+      }
     }
 
     if (this.options.localeData) {
@@ -70,6 +84,10 @@ class ICU {
     // so there is no need to add keys to that finalKeys array
     return finalKeys;
   }
+
+  clearCache() {
+    this.mem = {};
+  }
 }
 
 ICU.type = 'i18nFormat';

test/icu.spec.js

@@ -105,6 +105,26 @@ describe('icu format', () => {
       expect(i18next.t('key', { numPhotos: 2000 })).toEqual('You have 2,000 photos.');
     });
 
+    it('should clear the cache on bound events', () => {
+      i18next.use(ICU).init({
+        lng: 'en',
+        resources: {},
+        i18nFormat: {
+          memoize: true,
+          bindI18n: 'languageChanged',
+          bindI18nStore: 'added'
+        }
+      });
+
+      const spy = jest.spyOn(i18next.services.i18nFormat, 'clearCache');
+
+      expect(spy).not.toHaveBeenCalled();
+      i18next.changeLanguage('ar');
+      expect(spy).toHaveBeenCalledTimes(1);
+      i18next.addResourceBundle('en', 'translation', { key: 'value' });
+      expect(spy).toHaveBeenCalledTimes(2);
+    });
+
   });
 
 });