fix: imporve getNavigatorLanguages more cache strictly

build.config.ts

@@ -2,6 +2,9 @@ import { defineBuildConfig } from 'unbuild'
 
 export default defineBuildConfig({
   declaration: true,
+  replace: {
+    'import.meta.vitest': undefined,
+  },
   rollup: {
     emitCJS: true,
     inlineDependencies: true,
@@ -21,4 +24,18 @@ export default defineBuildConfig({
     },
   ],
   externals: ['h3'],
+  hooks: {
+    'rollup:options': (_ctx, options) => {
+      // deno-lint-ignore no-explicit-any
+      ;(options.plugins as any).push({
+        name: 'workaround-strip-in-source-test',
+        transform(code: string, _id: string) {
+          return {
+            code: code.replace(/import.meta.vitest/g, 'false'),
+            map: null,
+          }
+        },
+      })
+    },
+  },
 })

src/env.d.ts

@@ -6,3 +6,5 @@ declare namespace NodeJS {
     LANGUAGE?: string
   }
 }
+
+declare let __TEST__: boolean

src/node.test.ts

@@ -1,13 +1,11 @@
-import { afterEach, beforeEach, describe, expect, test } from 'vitest'
+import { describe, expect, test } from 'vitest'
 import supertest from 'supertest'
 import {
   getAcceptLanguage,
   getAcceptLanguages,
   getAcceptLocale,
   getAcceptLocales,
   getCookieLocale,
-  getNavigatorLanguage,
-  getNavigatorLanguages,
   setCookieLocale,
 } from './node.ts'
 import { createServer, IncomingMessage, OutgoingMessage } from 'node:http'
@@ -246,49 +244,3 @@ describe('setCookieLocale', () => {
       .toThrowError(/locale is invalid: j/)
   })
 })
-
-describe('getNavigatorLanguages', () => {
-  let orgEnv = {}
-  beforeEach(() => {
-    orgEnv = process.env
-  })
-  afterEach(() => {
-    process.env = orgEnv
-  })
-
-  test('basic', () => {
-    process.env.LC_ALL = 'en-GB'
-    process.env.LC_MESSAGES = 'en-US'
-    process.env.LANG = 'ja-JP'
-    process.env.LANGUAGE = 'en'
-
-    const values = [
-      'en-GB',
-      'en-US',
-      'ja-JP',
-      'en',
-    ]
-    expect(getNavigatorLanguages()).toEqual(values)
-    expect(getNavigatorLanguages()).toEqual(values)
-  })
-})
-
-describe('getNavigatorLanguage', () => {
-  let orgEnv = {}
-  beforeEach(() => {
-    orgEnv = process.env
-  })
-  afterEach(() => {
-    process.env = orgEnv
-  })
-
-  test('basic', () => {
-    process.env.LC_ALL = 'en-GB'
-    process.env.LC_MESSAGES = 'en-US'
-    process.env.LANG = 'ja-JP'
-    process.env.LANGUAGE = 'en'
-
-    expect(getNavigatorLanguage()).toEqual('en-GB')
-    expect(getNavigatorLanguage()).toEqual('en-GB')
-  })
-})

src/node.ts

@@ -220,7 +220,7 @@ let navigatorLanguages: string[] | undefined
  * @returns {Array<string>} {@link https://datatracker.ietf.org/doc/html/rfc4646#section-2.1 | BCP 47 language tags}, if you can't get the language tag, return an empty array.
  */
 export function getNavigatorLanguages(): readonly string[] {
-  if (navigatorLanguages) {
+  if (navigatorLanguages && navigatorLanguages.length > 0) {
     return navigatorLanguages
   }
 
@@ -235,7 +235,65 @@ export function getNavigatorLanguages(): readonly string[] {
   return navigatorLanguages = [...langs].filter(Boolean)
 }
 
-let navigatorLanguage: string | undefined
+/**
+ * in-source testing for `getNavigatorLanguages`
+ */
+if (import.meta.vitest) {
+  const { describe, test, expect, afterEach, vi } = import.meta.vitest
+
+  describe('getNavigatorLanguages', () => {
+    afterEach(() => {
+      vi.resetAllMocks()
+      navigatorLanguages = undefined
+    })
+
+    test('basic', () => {
+      vi.spyOn(process, 'env', 'get').mockReturnValue({
+        LC_ALL: 'en-GB',
+        LC_MESSAGES: 'en-US',
+        LANG: 'ja-JP',
+        LANGUAGE: 'en',
+      })
+
+      const values = [
+        'en-GB',
+        'en-US',
+        'ja-JP',
+        'en',
+      ]
+      expect(getNavigatorLanguages()).toEqual(values)
+      // cache checking
+      expect(navigatorLanguages).toEqual(values)
+    })
+
+    test('duplicate language', () => {
+      vi.spyOn(process, 'env', 'get').mockReturnValue({
+        LC_ALL: 'en-US',
+        LC_MESSAGES: 'en-US',
+        LANG: 'ja-JP',
+        LANGUAGE: 'ja-JP',
+      })
+
+      const values = [
+        'en-US',
+        'ja-JP',
+      ]
+      expect(getNavigatorLanguages()).toEqual(values)
+      // cache checking
+      expect(navigatorLanguages).toEqual(values)
+    })
+
+    test('language nothing', () => {
+      const mockEnv = vi.spyOn(process, 'env', 'get').mockReturnValue({})
+      expect(getNavigatorLanguages()).toEqual([])
+      expect(navigatorLanguages).toEqual([])
+      expect(getNavigatorLanguages()).toEqual([])
+      expect(mockEnv).toHaveBeenCalledTimes(2)
+    })
+  })
+}
+
+let navigatorLanguage = ''
 
 /**
  * get navigator languages
@@ -249,3 +307,52 @@ export function getNavigatorLanguage(): string {
   return navigatorLanguage ||
     (navigatorLanguage = getNavigatorLanguages()[0] || '')
 }
+
+/**
+ * in-source testing for `getNavigatorLanguage`
+ */
+if (import.meta.vitest) {
+  const { describe, test, expect, afterEach, vi } = import.meta.vitest
+
+  describe('getNavigatorLanguage', () => {
+    afterEach(() => {
+      vi.resetAllMocks()
+      navigatorLanguages = undefined
+      navigatorLanguage = ''
+    })
+
+    test('basic', () => {
+      vi.spyOn(process, 'env', 'get').mockReturnValue({
+        LC_ALL: 'en-GB',
+        LC_MESSAGES: 'en-US',
+        LANG: 'ja-JP',
+        LANGUAGE: 'en',
+      })
+
+      expect(getNavigatorLanguage()).toEqual('en-GB')
+      // cache checking
+      expect(navigatorLanguage).toEqual('en-GB')
+    })
+
+    test('duplicate language', () => {
+      vi.spyOn(process, 'env', 'get').mockReturnValue({
+        LC_ALL: 'en-US',
+        LC_MESSAGES: 'en-US',
+        LANG: 'ja-JP',
+        LANGUAGE: 'ja-JP',
+      })
+
+      expect(getNavigatorLanguage()).toEqual('en-US')
+      // cache checking
+      expect(navigatorLanguage).toEqual('en-US')
+    })
+
+    test('language nothing', () => {
+      const mockEnv = vi.spyOn(process, 'env', 'get').mockReturnValue({})
+      expect(getNavigatorLanguage()).toBe('')
+      expect(navigatorLanguage).toBe('')
+      expect(getNavigatorLanguage()).toBe('')
+      expect(mockEnv).toHaveBeenCalledTimes(2)
+    })
+  })
+}

tsconfig.json

@@ -32,7 +32,9 @@
     // "paths": {},                                      /* Specify a set of entries that re-map imports to additional lookup locations. */
     // "rootDirs": [],                                   /* Allow multiple folders to be treated as one when resolving modules. */
     // "typeRoots": [],                                  /* Specify multiple folders that act like './node_modules/@types'. */
-    // "types": [],                                      /* Specify type package names to be included without being referenced in a source file. */
+    "types": [
+      "vitest/importMeta"
+    ], /* Specify type package names to be included without being referenced in a source file. */
     // "allowUmdGlobalAccess": true,                     /* Allow accessing UMD globals from modules. */
     // "moduleSuffixes": [],                             /* List of file name suffixes to search when resolving a module. */
     "allowImportingTsExtensions": true, /* Allow imports to include TypeScript file extensions. Requires '--moduleResolution bundler' and either '--noEmit' or '--emitDeclarationOnly' to be set. */

vitest.config.ts

@@ -0,0 +1,7 @@
+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+  test: {
+    includeSource: ['src/**/*.{js,ts}'],
+  },
+})