feat: add getNavigatorLanguages, getNavigatorLanguage and normalizeLanguageName

README.md

@@ -126,9 +126,23 @@ You can play the below examples:
 - `isLocale`
 - `parseAcceptLanguage`
 - `validateLanguageTag`
+- `normalizeLanguageName`
 
 You can do `import { ... } from '@intlify/utils'` the above utilities
 
+### Navigator
+
+- `getNavigatorLanguages`
+- `getNavigatorLanguage`
+
+You can do `import { ... } from '@intlify/utils/{ENV}'` the above utilities.
+
+The namespace `{ENV}` is one of the following:
+
+- `node`: Node.js
+- `web`: JS environments (such as Deno, Bun, and Browser) supporting Web APIs
+  (`navigator.language(s)`)
+
 ### HTTP
 
 - `getAcceptLanguages`
@@ -148,10 +162,6 @@ The namespace `{ENV}` is one of the following:
   and [Response](https://developer.mozilla.org/en-US/docs/Web/API/Response)
 - `h3`: HTTP framework [h3](https://github.com/unjs/h3)
 
-### Browser
-
-TODO: WIP
-
 ## 🙌 Contributing guidelines
 
 If you are interested in contributing to `@intlify/utils`, I highly recommend

src/env.d.ts

@@ -0,0 +1,8 @@
+declare namespace NodeJS {
+  interface ProcessEnv {
+    LC_ALL?: string
+    LC_MESSAGES?: string
+    LANG?: string
+    LANGUAGE?: string
+  }
+}

src/node.test.ts

@@ -1,11 +1,13 @@
-import { describe, expect, test } from 'vitest'
+import { afterEach, beforeEach, 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'
@@ -244,3 +246,49 @@ 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

@@ -7,6 +7,7 @@ import {
   mapToLocaleFromLanguageTag,
   validateLocale,
 } from './http.ts'
+import { normalizeLanguageName } from './shared.ts'
 import { DEFAULT_COOKIE_NAME, DEFAULT_LANG_TAG } from './constants.ts'
 
 import type { CookieOptions } from './http.ts'
@@ -207,3 +208,44 @@ export function setCookieLocale(
   })
   response.setHeader('set-cookie', [...setCookies, target])
 }
+
+let navigatorLanguages: string[] | undefined
+
+/**
+ * get navigator languages
+ *
+ * @description
+ * You can get the language tags from system environment variables.
+ *
+ * @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) {
+    return navigatorLanguages
+  }
+
+  const env = process.env
+  const langs = new Set<string>()
+
+  env.LC_ALL && langs.add(normalizeLanguageName(env.LC_ALL))
+  env.LC_MESSAGES && langs.add(normalizeLanguageName(env.LC_MESSAGES))
+  env.LANG && langs.add(normalizeLanguageName(env.LANG))
+  env.LANGUAGE && langs.add(normalizeLanguageName(env.LANGUAGE))
+
+  return navigatorLanguages = [...langs].filter(Boolean)
+}
+
+let navigatorLanguage: string | undefined
+
+/**
+ * get navigator languages
+ *
+ * @description
+ * You can get the language tag from system environment variables.
+ *
+ * @returns {string} {@link https://datatracker.ietf.org/doc/html/rfc4646#section-2.1 | BCP 47 language tag}, if you can't get the language tag, return a enmpty string.
+ */
+export function getNavigatorLanguage(): string {
+  return navigatorLanguage ||
+    (navigatorLanguage = getNavigatorLanguages()[0] || '')
+}

src/shared.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, test } from 'vitest'
-import { isLocale, parseAcceptLanguage, validateLanguageTag } from './shared.ts'
+import {
+  isLocale,
+  normalizeLanguageName,
+  parseAcceptLanguage,
+  validateLanguageTag,
+} from './shared.ts'
 
 describe('isLocale', () => {
   test('Locale instance', () => {
@@ -51,3 +56,21 @@ describe('validateLanguageTag', () => {
     expect(validateLanguageTag('j')).toBe(false)
   })
 })
+
+describe('normalizeLanguageName', () => {
+  test('basic: en_US', () => {
+    expect(normalizeLanguageName('en_US')).toBe('en-US')
+  })
+
+  test('language only: en', () => {
+    expect(normalizeLanguageName('en')).toBe('en')
+  })
+
+  test('has encoding: en_US.UTF-8', () => {
+    expect(normalizeLanguageName('en_US.UTF-8')).toBe('en-US')
+  })
+
+  test('empty', () => {
+    expect(normalizeLanguageName('')).toBe('')
+  })
+})

src/shared.ts

@@ -41,3 +41,25 @@ export function validateLanguageTag(lang: string): boolean {
     return false
   }
 }
+
+/**
+ * nomralize the language name
+ *
+ * @description
+ * This function normalizes the locale name defined in {@link https://www.gnu.org/software/gettext/manual/gettext.html#Locale-Names | gettext(libc) style} to {@link https://datatracker.ietf.org/doc/html/rfc4646#section-2.1 | BCP 47 language tag}
+ *
+ * @example
+ * ```ts
+ * const oldLangName = 'en_US'
+ * const langTag = nomralizeLanguageName(oldLangName)
+ * conosle.log(langTag) // en-US
+ * ```
+ *
+ * @param langName The target language name
+ *
+ * @returns {string} The normalized language tag
+ */
+export function normalizeLanguageName(langName: string): string {
+  const [lang] = langName.split('.')
+  return lang.replace(/_/g, '-')
+}

src/web.test.ts

@@ -1,10 +1,12 @@
-import { describe, expect, test } from 'vitest'
+import { describe, expect, test, vi } from 'vitest'
 import {
   getAcceptLanguage,
   getAcceptLanguages,
   getAcceptLocale,
   getAcceptLocales,
   getCookieLocale,
+  getNavigatorLanguage,
+  getNavigatorLanguages,
   setCookieLocale,
 } from './web.ts'
 import { DEFAULT_COOKIE_NAME, DEFAULT_LANG_TAG } from './constants.ts'
@@ -175,3 +177,39 @@ describe('setCookieLocale', () => {
       .toThrowError(/locale is invalid: j/)
   })
 })
+
+describe('getNavigatorLanguages', () => {
+  test('basic', () => {
+    vi.stubGlobal('navigator', {
+      languages: ['en-US', 'en', 'ja'],
+    })
+
+    expect(getNavigatorLanguages()).toEqual(['en-US', 'en', 'ja'])
+  })
+
+  test('error', () => {
+    vi.stubGlobal('navigator', undefined)
+
+    expect(() => getNavigatorLanguages()).toThrowError(
+      /not support `navigator`/,
+    )
+  })
+})
+
+describe('getNavigatorLanguage', () => {
+  test('basic', () => {
+    vi.stubGlobal('navigator', {
+      language: 'en-US',
+    })
+
+    expect(getNavigatorLanguage()).toEqual('en-US')
+  })
+
+  test('error', () => {
+    vi.stubGlobal('navigator', undefined)
+
+    expect(() => getNavigatorLanguage()).toThrowError(
+      /not support `navigator`/,
+    )
+  })
+})

src/web.ts

@@ -210,3 +210,37 @@ export function setCookieLocale(
   })
   response.headers.set('set-cookie', [...setCookies, target].join('; '))
 }
+
+/**
+ * get navigator languages
+ *
+ * @description
+ * The value depends on the environments. if you use this function on the browser, you can get the languages, that are set in the browser, else if you use this function on the server side (Deno only), that value is the languages set in the server.
+ *
+ * @throws Throws the {@link Error} if the `navigator` is not exists.
+ *
+ * @returns {Array<string>} {@link https://datatracker.ietf.org/doc/html/rfc4646#section-2.1 | BCP 47 language tags}
+ */
+export function getNavigatorLanguages(): readonly string[] {
+  if (typeof navigator === 'undefined') {
+    throw new Error('not support `navigator`')
+  }
+  return navigator.languages
+}
+
+/**
+ * get navigator language
+ *
+ * @description
+ * The value depends on the environments. if you use this function on the browser, you can get the languages, that are set in the browser, else if you use this function on the server side (Deno only), that value is the language set in the server.
+ *
+ * @throws Throws the {@link Error} if the `navigator` is not exists.
+ *
+ * @returns {string} {@link https://datatracker.ietf.org/doc/html/rfc4646#section-2.1 | BCP 47 language tag}
+ */
+export function getNavigatorLanguage(): string {
+  if (typeof navigator === 'undefined') {
+    throw new Error('not support `navigator`')
+  }
+  return navigator.language
+}