From 2b28702451978628a0391285ddff0b0bae748c60 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Ch=C5=82odnicki?= <rchl2k@gmail.com>
Date: Sun, 2 Aug 2020 22:05:25 +0200
Subject: [PATCH] fix(lazy): include default locale in the main bundle

This avoid extra request for the locale that is always needed anyway.

Resolves #818
---
 src/index.js           | 24 ++++++++++++++++++++++++
 src/templates/utils.js | 21 +++++++++++++++------
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/src/index.js b/src/index.js
index 6ff946c6d..d2f450daf 100644
--- a/src/index.js
+++ b/src/index.js
@@ -35,6 +35,29 @@ module.exports = function (userOptions) {
     return
   }
 
+  let defaultLangFile
+
+  // Copy lang files to the build directory.
+  if (options.langDir) {
+    if (!options.locales.length || typeof options.locales[0] === 'string') {
+      console.warn('[' + options.MODULE_NAME + '] When using "langDir" option, the "locales" option must be a list of objects')
+    }
+
+    const uniqueFiles = new Set(options.locales.map(locale => locale.file))
+
+    if (options.defaultLocale) {
+      defaultLangFile = options.locales.find(locale => locale.code === options.defaultLocale).file
+    }
+
+    for (const file of uniqueFiles) {
+      const isUsingDefaultLangFile = file === defaultLangFile
+      this.addTemplate({
+        src: resolve(this.options.srcDir, options.langDir, file),
+        fileName: join(ROOT_DIR, (isUsingDefaultLangFile ? 'default-lang' : 'langs'), file)
+      })
+    }
+  }
+
   const localeCodes = getLocaleCodes(options.locales)
   const { trailingSlash } = this.options.router
 
@@ -48,6 +71,7 @@ module.exports = function (userOptions) {
     LOCALE_FILE_KEY,
     STRATEGIES,
     COMPONENT_OPTIONS_KEY,
+    defaultLangFile,
     localeCodes,
     trailingSlash
   }
diff --git a/src/templates/utils.js b/src/templates/utils.js
index 97cb8e021..6670fde60 100755
--- a/src/templates/utils.js
+++ b/src/templates/utils.js
@@ -1,8 +1,12 @@
 import {
   LOCALE_CODE_KEY,
   LOCALE_FILE_KEY,
-  MODULE_NAME
+  MODULE_NAME,
+  defaultLangFile
 } from './options'
+/* <% if (options.defaultLangFile) { %> */
+import defaultLangModule from './default-lang/<%= options.defaultLangFile %>'
+/* <% } %> */
 
 /**
  * Asynchronously load messages from translation files
@@ -17,15 +21,20 @@ export async function loadLanguageAsync (context, locale) {
   }
 
   if (!app.i18n.loadedLanguages.includes(locale)) {
-    const langOptions = app.i18n.locales.find(l => l[LOCALE_CODE_KEY] === locale)
-    if (langOptions) {
-      const file = langOptions[LOCALE_FILE_KEY]
+    const localeObject = app.i18n.locales.find(l => l[LOCALE_CODE_KEY] === locale)
+    if (localeObject) {
+      const file = localeObject[LOCALE_FILE_KEY]
       if (file) {
         // Hiding template directives from eslint so that parsing doesn't break.
         /* <% if (options.langDir) { %> */
         try {
-          const module = await import(/* webpackChunkName: "lang-[request]" */ '~/<%= options.langDir %>' + file)
-          const messages = module.default ? module.default : module
+          let langFileModule
+          if (file === defaultLangFile) {
+            langFileModule = defaultLangModule
+          } else {
+            langFileModule = await import(/* webpackChunkName: "lang-[request]" */ `./langs/${file}`)
+          }
+          const messages = langFileModule.default || langFileModule
           const result = typeof messages === 'function' ? await Promise.resolve(messages(context, locale)) : messages
           app.i18n.setLocaleMessage(locale, result)
           app.i18n.loadedLanguages.push(locale)