1 files changed, 9 insertions, 1 deletions
diff --git a/packages/gitbook-core/src/reducers/index.js b/packages/gitbook-core/src/reducers/index.js
index 05ff70f..dae1f9c 100644
--- a/packages/gitbook-core/src/reducers/index.js
+++ b/packages/gitbook-core/src/reducers/index.js
@@ -1,5 +1,13 @@
 const Redux = require('redux');
 
+const identity = ((state, action) => state || {});
+
 module.exports = Redux.combineReducers({
-    components: require('./components')
+    components: require('./components'),
+    navigation: require('./navigation'),
+
+    // GitBook JSON
+    page:    identity,
+    summary: identity,
+    readme:  identity
 });