From 89f3a5177b830d03e1d7777174ae264c8e9944ac Mon Sep 17 00:00:00 2001
From: PanAeon <vitalii.voloshyn@gmail.com>
Date: Mon, 22 Oct 2018 16:47:20 +0100
Subject: [PATCH 1/2] Generate alternate url for different locales so search
 engine could find them all.

---
 src/js/app/index.js          | 20 +++++++++++++++++++-
 src/js/stores/LocaleStore.js |  7 +++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/src/js/app/index.js b/src/js/app/index.js
index 69e1fdce..072b7945 100644
--- a/src/js/app/index.js
+++ b/src/js/app/index.js
@@ -1,6 +1,7 @@
 var Backbone = require('backbone');
 var EventEmitter = require('events').EventEmitter;
 var React = require('react');
+var _ = require('underscore');
 
 var assign = require('object-assign');
 var util = require('../util');
@@ -86,6 +87,22 @@ var vcsModeRefresh = function(eventData) {
   $('body').toggleClass('hgMode', !isGit);
 };
 
+var insertAlternateLinks = function(pageId) {
+  // For now pageId is null, which would link to the main page.
+  // In future if pageId is provided this method should link to a specific page
+
+  // The value of the hreflang attribute identifies the language (in ISO 639-1 format)
+  // and optionally a region (in ISO 3166-1 Alpha 2 format) of an alternate URL
+  var altLinks = _.map(LocaleStore.getSupportedLocales(), function(langCode) {
+    var url = "https://learngitbranching.js.org/?locale=" + langCode;
+    return '<link rel="alternate" hreflang="'+langCode+'" href="' + url +'" />';
+  });
+  var defaultUrl = "https://learngitbranching.js.org/?locale=" + LocaleStore.getDefaultLocale();
+  altLinks.push('<link rel="alternate" hreflang="x-default" href="' + defaultUrl +'" />');
+  $('head').prepend(altLinks);
+
+};
+
 var intlRefresh = function() {
   if (!window.$) { return; }
   $('span.intl-aware').each(function(i, el) {
@@ -249,6 +266,8 @@ var initDemo = function(sandbox) {
     tryLocaleDetect();
   }
 
+  insertAlternateLinks();
+
   if (params.command) {
     var command = unescape(params.command);
     sandbox.mainVis.customEvents.on('gitEngineReady', function() {
@@ -328,4 +347,3 @@ exports.getLevelDropdown = function() {
 };
 
 exports.init = init;
-
diff --git a/src/js/stores/LocaleStore.js b/src/js/stores/LocaleStore.js
index 3b1a27b4..227bdd67 100644
--- a/src/js/stores/LocaleStore.js
+++ b/src/js/stores/LocaleStore.js
@@ -3,6 +3,7 @@
 var AppConstants = require('../constants/AppConstants');
 var AppDispatcher = require('../dispatcher/AppDispatcher');
 var EventEmitter = require('events').EventEmitter;
+var _ = require('underscore');
 
 var assign = require('object-assign');
 
@@ -30,6 +31,8 @@ var headerLocaleMap = {
   'pt-BR': 'pt_BR'
 };
 
+var supportedLocalesList = _.values(langLocaleMap).concat(_.values(headerLocaleMap));
+
 function _getLocaleFromHeader(langString) {
   var languages = langString.split(',');
   var desiredLocale;
@@ -73,6 +76,10 @@ AppConstants.StoreSubscribePrototype,
     return _locale;
   },
 
+  getSupportedLocales: function() {
+    return assign({}, supportedLocalesList);
+  },
+
   dispatchToken: AppDispatcher.register(function(payload) {
     var action = payload.action;
     var shouldInform = false;

From 9d14feb1b39751ebddcd39efed3444bc25413381 Mon Sep 17 00:00:00 2001
From: PanAeon <vitalii.voloshyn@gmail.com>
Date: Wed, 24 Oct 2018 11:12:48 +0100
Subject: [PATCH 2/2] Requested changes - removed underscore and sorted out
 duplicates in locales

---
 src/js/app/index.js          | 4 ++--
 src/js/stores/LocaleStore.js | 7 ++++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/js/app/index.js b/src/js/app/index.js
index 072b7945..82e66870 100644
--- a/src/js/app/index.js
+++ b/src/js/app/index.js
@@ -1,7 +1,6 @@
 var Backbone = require('backbone');
 var EventEmitter = require('events').EventEmitter;
 var React = require('react');
-var _ = require('underscore');
 
 var assign = require('object-assign');
 var util = require('../util');
@@ -93,7 +92,8 @@ var insertAlternateLinks = function(pageId) {
 
   // The value of the hreflang attribute identifies the language (in ISO 639-1 format)
   // and optionally a region (in ISO 3166-1 Alpha 2 format) of an alternate URL
-  var altLinks = _.map(LocaleStore.getSupportedLocales(), function(langCode) {
+
+  var altLinks = LocaleStore.getSupportedLocales().map(function(langCode) {
     var url = "https://learngitbranching.js.org/?locale=" + langCode;
     return '<link rel="alternate" hreflang="'+langCode+'" href="' + url +'" />';
   });
diff --git a/src/js/stores/LocaleStore.js b/src/js/stores/LocaleStore.js
index 227bdd67..544a5af7 100644
--- a/src/js/stores/LocaleStore.js
+++ b/src/js/stores/LocaleStore.js
@@ -3,7 +3,6 @@
 var AppConstants = require('../constants/AppConstants');
 var AppDispatcher = require('../dispatcher/AppDispatcher');
 var EventEmitter = require('events').EventEmitter;
-var _ = require('underscore');
 
 var assign = require('object-assign');
 
@@ -31,7 +30,9 @@ var headerLocaleMap = {
   'pt-BR': 'pt_BR'
 };
 
-var supportedLocalesList = _.values(langLocaleMap).concat(_.values(headerLocaleMap));
+var supportedLocalesList = Object.values(langLocaleMap)
+                                 .concat(Object.values(headerLocaleMap))
+                                 .filter(function (value, index, self) { return self.indexOf(value) === index;});
 
 function _getLocaleFromHeader(langString) {
   var languages = langString.split(',');
@@ -77,7 +78,7 @@ AppConstants.StoreSubscribePrototype,
   },
 
   getSupportedLocales: function() {
-    return assign({}, supportedLocalesList);
+    return supportedLocalesList.slice();
   },
 
   dispatchToken: AppDispatcher.register(function(payload) {