1 files changed, 34 insertions, 0 deletions
diff --git a/packages/gitbook/src/api/decodePage.js b/packages/gitbook/src/api/decodePage.js
new file mode 100644
index 0000000..16e5115
--- /dev/null
+++ b/packages/gitbook/src/api/decodePage.js
@@ -0,0 +1,34 @@
+const Immutable = require('immutable');
+
+/**
+ * Decode changes from a JS API to a page object.
+ * Only the content can be edited by plugin's hooks.
+ *
+ * @param {Output} output
+ * @param {Page} page: page instance to edit
+ * @param {Object} result: result from API
+ * @return {Page}
+ */
+function decodePage(output, page, result) {
+    const originalContent = page.getContent();
+
+    // No returned value
+    // Existing content will be used
+    if (!result) {
+        return page;
+    }
+
+    // Update page attributes
+    const newAttributes = Immutable.fromJS(result.attributes);
+    page = page.set('attributes', newAttributes);
+
+    // GitBook 3
+    // Use returned page.content if different from original content
+    if (result.content != originalContent) {
+        page = page.set('content', result.content);
+    }
+
+    return page;
+}
+
+module.exports = decodePage;