diff --git a/blocks/navigation/yui/navigation/navigation.js b/blocks/navigation/yui/navigation/navigation.js
index 364b0ecdaa3..62f417e5ce9 100644
--- a/blocks/navigation/yui/navigation/navigation.js
+++ b/blocks/navigation/yui/navigation/navigation.js
@@ -74,6 +74,35 @@ var EXPANSIONLIMIT_EVERYTHING = 0,
     EXPANSIONLIMIT_SECTION    = 30,
     EXPANSIONLIMIT_ACTIVITY   = 40;
 
+/**
+ * Mappings for the different types of nodes coming from the navigation.
+ * Copied from lib/navigationlib.php navigation_node constants.
+ * @type object
+ */
+var NODETYPE = {
+    /** @type int Root node = 0 */
+    ROOTNODE : 0,
+    /** @type int System context = 1 */
+    SYSTEM : 1,
+    /** @type int Course category = 10 */
+    CATEGORY : 10,
+    /** @type int Course = 20 */
+    COURSE : 20,
+    /** @type int Course section = 30 */
+    SECTION : 30,
+    /** @type int Activity (course module) = 40 */
+    ACTIVITY : 40,
+    /** @type int Resource (course module = 50 */
+    RESOURCE : 50,
+    /** @type int Custom node (could be anything) = 60 */
+    CUSTOM : 60,
+    /** @type int Setting = 70 */
+    SETTING : 70,
+    /** @type int User context = 80 */
+    USER : 80,
+    /** @type int Container = 90 */
+    CONTAINER : 90
+}
 
 /**
  * Navigation tree class.
@@ -299,7 +328,7 @@ BRANCH.prototype = {
         // Prepare the icon, should be an object representing a pix_icon
         var branchicon = false;
         var icon = this.get('icon');
-        if (icon && (!isbranch || this.get('type') == 40)) {
+        if (icon && (!isbranch || this.get('type') == NODETYPE.ACTIVITY)) {
             branchicon = Y.Node.create('<img alt="" />');
             branchicon.setAttribute('src', M.util.image_url(icon.pix, icon.component));
             branchli.addClass('item_with_icon');
@@ -419,13 +448,13 @@ BRANCH.prototype = {
                 var coursecount = 0;
                 for (var i in object.children) {
                     if (typeof(object.children[i])=='object') {
-                        if (object.children[i].type == 20) {
+                        if (object.children[i].type == NODETYPE.COURSE) {
                             coursecount++;
                         }
                         this.addChild(object.children[i]);
                     }
                 }
-                if ((this.get('type') == 10 || this.get('type') == 0) && coursecount >= M.block_navigation.courselimit) {
+                if ((this.get('type') == NODETYPE.CATEGORY || this.get('type') == NODETYPE.ROOTNODE) && coursecount >= M.block_navigation.courselimit) {
                     this.addViewAllCoursesChild(this);
                 }
                 this.get('tree').toggleExpansion({target:this.node});
@@ -450,14 +479,14 @@ BRANCH.prototype = {
             var count = 0, i, children = branch.get('children');
             for (i in children) {
                 // Add each branch to the tree
-                if (children[i].type == 20) {
+                if (children[i].type == NODETYPE.COURSE) {
                     count++;
                 }
                 if (typeof(children[i])=='object') {
                     branch.addChild(children[i]);
                 }
             }
-            if (branch.get('type') == 10 && count >= M.block_navigation.courselimit) {
+            if (branch.get('type') == NODETYPE.CATEGORY && count >= M.block_navigation.courselimit) {
                 this.addViewAllCoursesChild(branch);
             }
         }
@@ -469,14 +498,14 @@ BRANCH.prototype = {
      */
     addViewAllCoursesChild: function(branch) {
         var url = null;
-        if (branch.get('type') == 0 ) {
-            if (branch.get('key') == 'mycourses') {
-                url = M.cfg.wwwroot+'/my';
+        if (branch.get('type') == NODETYPE.ROOTNODE) {
+            if (branch.get('key') === 'mycourses') {
+                url = M.cfg.wwwroot + '/my';
             } else {
-                url = M.cfg.wwwroot+'/course/index.php';
+                url = M.cfg.wwwroot + '/course/index.php';
             }
         } else {
-            url = M.cfg.wwwroot+'/course/category.php?id='+branch.get('key');
+            url = M.cfg.wwwroot+'/course/category.php?id=' + branch.get('key');
         }
         branch.addChild({
             name : M.str.moodle.viewallcourses,
diff --git a/lib/ajax/getnavbranch.php b/lib/ajax/getnavbranch.php
index d3e2cec2ad0..e42d63a74a1 100644
--- a/lib/ajax/getnavbranch.php
+++ b/lib/ajax/getnavbranch.php
@@ -35,7 +35,9 @@ require_once($CFG->dirroot.'/course/lib.php');
 try {
     // Start buffer capture so that we can `remove` any errors
     ob_start();
-    // Require id This is the key for whatever branch we want to get
+    // Require id This is the key for whatever branch we want to get.
+    // This accepts alphanum because the courses and my courses branches don't have numerical keys.
+    // For those branches we return the alphanum key, courses and mycourses.
     $branchid = required_param('id', PARAM_ALPHANUM);
     // This identifies the type of the branch we want to get
     $branchtype = required_param('type', PARAM_INT);