fix if not plugins passed

wax-prosemirror-core/src/Wax.js

@@ -43,9 +43,11 @@ class Wax extends Component {
     const editorContent = value ? value : "";
 
     defaultPlugins.push(
-      ...[placeholder({ content: this.props.placeholder }), ...plugins, keys]
+      ...[placeholder({ content: this.props.placeholder }), keys]
     );
 
+    if (plugins) defaultPlugins.push(...plugins);
+
     this.WaxOptions = {
       schema,
       plugins: defaultPlugins