Add immutable state for readme/summary

Add shapes for these states

1 files changed, 6 insertions, 1 deletions

diff --git a/packages/gitbook-core/src/shapes/Page.js b/packages/gitbook-core/src/shapes/Page.js
index 11117fe..c589f54 100644
--- a/packages/gitbook-core/src/shapes/Page.js
+++ b/packages/gitbook-core/src/shapes/Page.js
@@ -1,11 +1,16 @@
 const React  = require('react');
 const {
+    oneOf,
     string,
+    number,
     shape
 } = React.PropTypes;
 
 
 module.exports = shape({
     title:   string.isRequired,
-    content: string.isRequired
+    content: string.isRequired,
+    level:   string.isRequired,
+    depth:   number.isRequired,
+    dir:     oneOf(['ltr', 'rtl']).isRequired
 });