1 files changed, 12 insertions, 6 deletions
diff --git a/lib/api/encodeNavigation.js b/lib/api/encodeNavigation.js
index c48ba50..8e329a1 100644
--- a/lib/api/encodeNavigation.js
+++ b/lib/api/encodeNavigation.js
@@ -1,3 +1,4 @@
+var Immutable = require('immutable');
 
 /**
     Encode an article for next/prev
@@ -26,13 +27,15 @@ function encodeArticle(pages, article) {
 */
 function encodeNavigation(output) {
     var book = output.getBook();
+    var pages = output.getPages();
     var summary = book.getSummary();
     var articles = summary.getArticlesAsList();
 
-    return articles
+
+    var navigation = articles
         .map(function(article, i) {
             var ref = article.getRef();
-            if (ref) {
+            if (!ref) {
                 return undefined;
             }
 
@@ -45,14 +48,17 @@ function encodeNavigation(output) {
                     index: i,
                     title: article.getTitle(),
                     introduction: (i === 0),
-                    prev: prev? encodeArticle(prev) : undefined,
-                    next: next? encodeArticle(next) : undefined,
+                    prev: prev? encodeArticle(pages, prev) : undefined,
+                    next: next? encodeArticle(pages, next) : undefined,
                     level: article.getLevel()
                 }
             ];
         })
-        .toMap()
-        .toJS();
+        .filter(function(e) {
+            return Boolean(e);
+        });
+
+    return Immutable.Map(navigation).toJS();
 }
 
 module.exports = encodeNavigation;