Handle nonexistent locale switch

package.json

@@ -1,6 +1,6 @@
 {
   "name": "svelte-i18n",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "license": "MIT",
   "main": "dist/i18n.js",
   "module": "dist/i18n.m.js",

src/index.js

@@ -5,9 +5,9 @@ import Formatter from './formatter'
 
 export { capital, title, upper, lower }
 
-export function i18n(store, { dictionary }) {
+export function i18n(store, { dictionary: initialDictionary }) {
   const formatter = new Formatter()
-  let dictionaries = {}
+  let dictionary = {}
   let currentLocale
 
   const getLocalizedMessage = (
@@ -16,7 +16,7 @@ export function i18n(store, { dictionary }) {
     locale = currentLocale,
     transformers = undefined,
   ) => {
-    let message = resolvePath(dictionaries[locale], path)
+    let message = resolvePath(dictionary[locale], path)
 
     if (!message) return path
 
@@ -57,25 +57,33 @@ export function i18n(store, { dictionary }) {
     },
   }
 
+  store.on('locale', newLocale => {
+    if (!Object.keys(dictionary).includes(newLocale)) {
+      console.error(`[svelte-i18n] Couldn't find the "${newLocale}" locale.`)
+      return
+    }
+    currentLocale = newLocale
+    const _ = getLocalizedMessage
+
+    _.upper = utilities.upper
+    _.lower = utilities.lower
+    _.title = utilities.title
+    _.capital = utilities.capital
+    _.plural = utilities.plural
+
+    store.set({ locale: newLocale, _ })
+  })
+
   store.i18n = {
     setLocale(locale) {
       store.fire('locale', locale)
     },
     extendDictionary(...list) {
-      dictionaries = deepmerge.all([dictionaries, ...list])
+      dictionary = deepmerge.all([dictionary, ...list])
     },
   }
 
-  store.i18n.extendDictionary(dictionary)
-
-  store.on('locale', newLocale => {
-    currentLocale = newLocale
-    const _ = getLocalizedMessage
-
-    Object.assign(_, utilities)
-
-    store.set({ locale: newLocale, _ })
-  })
+  store.i18n.extendDictionary(initialDictionary)
 
   return store
 }

test/index.test.js

@@ -42,6 +42,14 @@ describe('Utilities', () => {
 })
 
 describe('Localization', () => {
+  beforeEach(() => {
+    console.error = jest.fn()
+  })
+
+  afterEach(() => {
+    console.error.mockRestore()
+  })
+
   it('should start with a clean store', () => {
     const { _, locale } = store.get()
     expect(locale).toBeFalsy()
@@ -49,10 +57,10 @@ describe('Localization', () => {
   })
 
   it('should change the locale after a "locale" store event', () => {
-    store.fire('locale', 'en')
+    store.fire('locale', 'pt-br')
     const { locale, _ } = store.get()
 
-    expect(locale).toBe('en')
+    expect(locale).toBe('pt-br')
     expect(_).toBeInstanceOf(Function)
   })
 
@@ -65,6 +73,11 @@ describe('Localization', () => {
     expect(locale).toBe('pt-br')
   })
 
+  it('should handle nonexistent locale', () => {
+    expect(store.i18n.setLocale('foo'))
+    expect(console.error).toHaveBeenCalledTimes(1)
+  })
+
   it('should return the message id when no message identified by it was found', () => {
     store.i18n.setLocale('pt-br')
     const { _ } = store.get()