Update review comments

The following review comments are included in the commit:
- https://github.com/elastic/kibana/pull/7545#discussion_r74663515
- https://github.com/elastic/kibana/pull/7545#discussion_r74666995
- https://github.com/elastic/kibana/pull/7545#discussion_r74805552

src/core_plugins/i18n/server/i18n/i18n.js

@@ -60,6 +60,19 @@ function getLocaleFromFileName(fullFileName) {
   return locale;
 }
 
+/**
+ * The translation file is registered with i18n plugin. The plugin contains a list of registered translation file paths per language.
+ * @param {string} absolutePluginTranslationFilePath - Absolute path to the translation file to register.
+ */
 module.exports.registerTranslations = registerTranslations;
+/**
+ * Return all translations registered for a particular locale. If a translation is unavailable for the locale then default locale is used.
+ * @param {string} locale - Translation locale to be returned
+ * @return {Promise} - A Promise object which will contain on resolve a JSON object of all registered translations
+ */
 module.exports.getRegisteredLocaleTranslations = getRegisteredLocaleTranslations;
+/**
+ * Returns list of all registered locales.
+ * @return {list} - Registered locales
+ */
 module.exports.getRegisteredTranslationLocales = getRegisteredTranslationLocales;

src/core_plugins/i18n/server/i18n/index.js

@@ -1,35 +0,0 @@
-import  i18n from './i18n';
-
-/*
- Manages the locale translations for Kibana. Responsible for loading translated content per locale.
-
-API:
-
-Register translations:
-  registerTranslations(<absolute_path_to_translation_file>)
-  The translation file is registered with i18n plugin. The plugin contains a list of registered translation file paths per language.
-
-Fetch the list of currently supported locales:
-  List getRegisteredTranslationLocales()
-  Returns a list of all locales as locale codes for which translations are registered
-
-Fetch a specific locale translated content bundle:
-  Promise getRegisteredLocaleTranslations(<locale_code>)
-  Returns a Promise object which will contain on resolve a JSON object of all registered translations for the locale code specified
-*/
-
-let registerTranslations = function (absolutePluginTranslationFilePath) {
-  return i18n.registerTranslations(absolutePluginTranslationFilePath);
-};
-
-let getRegisteredLocaleTranslations = function (locale) {
-  return i18n.getRegisteredLocaleTranslations(locale);
-};
-
-let getRegisteredTranslationLocales = function () {
-  return i18n.getRegisteredTranslationLocales();
-};
-
-module.exports.registerTranslations = registerTranslations;
-module.exports.getRegisteredLocaleTranslations = getRegisteredLocaleTranslations;
-module.exports.getRegisteredTranslationLocales = getRegisteredTranslationLocales;

src/core_plugins/kibana/index.js

@@ -1,7 +1,7 @@
 import Promise from 'bluebird';
 import { mkdirp as mkdirpNode } from 'mkdirp';
 import manageUuid from './server/lib/manage_uuid';
-import i18nPlugin from '../i18n/server/i18n/index';
+import i18nPlugin from '../i18n/server/i18n/i18n';
 import ingest from './server/routes/api/ingest';
 import fromRoot from '../../utils/from_root';
 import search from './server/routes/api/search';
@@ -126,6 +126,5 @@ module.exports = function (kibana) {
 function registerCoreTranslations()
 {
   const corePluginTranslationFile = fromRoot('/src/core_plugins/kibana/i18n/en.json');
-  console.log('!! Regsiter file: ', corePluginTranslationFile);
   i18nPlugin.registerTranslations(corePluginTranslationFile);
 }

src/ui/index.js

@@ -10,7 +10,7 @@ import UiExports from './ui_exports';
 import UiBundle from './ui_bundle';
 import UiBundleCollection from './ui_bundle_collection';
 import UiBundlerEnv from './ui_bundler_env';
-import i18nPlugin from '../core_plugins/i18n/server/i18n/index';
+import i18nPlugin from '../core_plugins/i18n/server/i18n/i18n';
 import langParser from 'accept-language-parser';
 
 let kibanaTranslations = [];
@@ -144,11 +144,19 @@ function translate(key) {
 
 function getTranslationLocale(acceptLanguages) {
   let localeStr = '';
-  let foundLang = false;
 
   if (acceptLanguages === null || acceptLanguages.length <= 0) {
     return DEFAULT_LOCALE;
   }
+  localeStr = getTranslationLocaleExactMatch(acceptLanguages);
+  if (localeStr != null) {
+    return localeStr;
+  }
+  localeStr = getTranslationLocaleBestCaseMatch(acceptLanguages);
+}
+
+function getTranslationLocaleExactMatch(acceptLanguages) {
+  let localeStr = '';
 
   const acceptLangsLen = acceptLanguages.length;
   const registeredLocales = i18nPlugin.getRegisteredTranslationLocales();
@@ -161,14 +169,16 @@ function getTranslationLocale(acceptLanguages) {
       localeStr = language.code;
     }
     if (registeredLocales.indexOf(localeStr) > -1) {
-      foundLang = true;
-      break;
+      return localeStr;
     }
   }
-  if (foundLang) {
-    return localeStr;
-  }
+  return null;
+}
 
+function getTranslationLocaleBestCaseMatch(acceptLanguages, registeredLocales) {
+  let localeStr = '';
+
+  const acceptLangsLen = acceptLanguages.length;
   const regLangsLen = registeredLocales.length;
   for (let indx = 0; indx < acceptLangsLen; indx++) {
     const language = acceptLanguages[indx];
@@ -176,18 +186,9 @@ function getTranslationLocale(acceptLanguages) {
     for (let regIndx = 0; regIndx < regLangsLen; regIndx++) {
       const locale = registeredLocales[regIndx];
       if (locale.match('^' + locale)) {
-        localeStr = locale;
-        foundLang = true;
-        break;
+        return locale;
       }
     }
-    if (foundLang) {
-      break;
-    }
   }
-  if (foundLang) {
-    return localeStr;
-  }
-
   return DEFAULT_LOCALE;
 }