1 files changed, 31 insertions, 0 deletions
diff --git a/packages/gitbook-core/src/lib/createPlugin.js b/packages/gitbook-core/src/lib/createPlugin.js
new file mode 100644
index 0000000..7a49053
--- /dev/null
+++ b/packages/gitbook-core/src/lib/createPlugin.js
@@ -0,0 +1,31 @@
+
+const defaultInit = ((dispatch, getState) => {});
+const defaultReduce = ((state, action) => state);
+
+/**
+ * Create a plugin to extend the state and the views.
+ *
+ * @param  {Function(dispatch, state)} onInitialState
+ * @param  {Funciton(state, action)} onReduceState
+ * @return {Plugin}
+ */
+function createPlugin({ init, reduce, actions }) {
+    init = init || defaultInit;
+    reduce = reduce || defaultReduce;
+    actions = actions || {};
+
+    const plugin = {
+        init,
+        reduce,
+        actions
+    };
+
+    if (typeof window !== 'undefined') {
+        window.gitbookPlugins = window.gitbookPlugins || [];
+        window.gitbookPlugins.push(plugin);
+    }
+
+    return plugin;
+}
+
+module.exports = createPlugin;