Moved i18n basePath concept from themes to core

- we need the basePath concept for the main i18n class so we can pull it out into a module
- we already had this in the themeI18n class, so I just had to move it up
- also I added a default of __dirname, so we don't have to declare this constantly in the tests

core/frontend/services/theme-engine/i18n/i18n.js

@@ -11,21 +11,6 @@ class ThemeI18n extends i18n.I18n {
         super(options);
         // We don't care what gets passed in, themes use fulltext mode
         this._stringMode = 'fulltext';
-        this._basePath = options.basePath;
-    }
-
-    /**
-     * BasePath getter & setter used for testing
-     */
-    set basePath(basePath) {
-        this._basePath = basePath;
-    }
-
-    /**
-     * Need to call init after this
-     */
-    get basePath() {
-        return this._basePath;
     }
 
     /**

core/shared/i18n/i18n.js

@@ -13,11 +13,13 @@ const get = require('lodash/get');
 class I18n {
     /**
      * @param {objec} [options]
+     * @param {string} basePath - the base path to the translations directory
      * @param {string} [locale] - a locale string
      * @param {{dot|fulltext}} [stringMode] - which mode our translation keys use
      * @param {{object}} [logging] - logging method
      */
     constructor(options = {}) {
+        this._basePath = options.basePath || __dirname;
         this._locale = options.locale || this.defaultLocale();
         this._stringMode = options.stringMode || 'dot';
         this._logging = options.logging || console;
@@ -25,6 +27,20 @@ class I18n {
         this._strings = null;
     }
 
+    /**
+     * BasePath getter & setter used for testing
+     */
+    set basePath(basePath) {
+        this._basePath = basePath;
+    }
+
+    /**
+         * Need to call init after this
+         */
+    get basePath() {
+        return this._basePath;
+    }
+
     /**
      * English is our default locale
      */
@@ -185,7 +201,7 @@ class I18n {
     }
 
     _translationFileDirs() {
-        return [__dirname, 'translations'];
+        return [this.basePath];
     }
 
     // If we are passed a locale, use that, else use this.locale

core/shared/i18n/index.js

@@ -1,6 +1,6 @@
+const path = require('path');
 const logging = require('../logging');
-
 const I18n = require('./i18n');
 
-module.exports = new I18n({logging});
+module.exports = new I18n({logging, basePath: path.join(__dirname, 'translations')});
 module.exports.I18n = I18n;