diff --git a/extraPlugin/extra-plugin.js b/extraPlugin/extra-plugin.js
index 929ded818..20aa22cde 100644
--- a/extraPlugin/extra-plugin.js
+++ b/extraPlugin/extra-plugin.js
@@ -17,7 +17,7 @@ const extraRoutesPlugin = (route, options) => {
   return [];
 };
 
-extraRoutesPlugin[configValidator] = async options => {
+const validator = async options => {
   const errors = [];
 
   if (options.numberOfPages && typeof options.numberOfPages !== 'number') {
@@ -42,5 +42,5 @@ extraRoutesPlugin[configValidator] = async options => {
   return errors;
 };
 
-registerPlugin('router', 'extra', extraRoutesPlugin);
+registerPlugin('router', 'extra', extraRoutesPlugin, validator);
 module.exports.extraRoutesPlugin = extraRoutesPlugin;
diff --git a/extraPlugin/tocPlugin.js b/extraPlugin/tocPlugin.js
index 9fddb4dc0..30c6b81d4 100644
--- a/extraPlugin/tocPlugin.js
+++ b/extraPlugin/tocPlugin.js
@@ -24,5 +24,5 @@ const tocPlugin = async (html, options) => {
   return html;
 };
 
-tocPlugin[configValidator] = async config => [];
-registerPlugin('render', 'toc', tocPlugin);
+const validator = async config => [];
+registerPlugin('render', 'toc', tocPlugin, validator);
diff --git a/extraPlugin/voidPlugin.js b/extraPlugin/voidPlugin.js
index 3ec9af6bf..60f4cac3c 100644
--- a/extraPlugin/voidPlugin.js
+++ b/extraPlugin/voidPlugin.js
@@ -9,5 +9,5 @@ const voidPlugin = async (route, options) => {
   return [];
 };
 
-voidPlugin[configValidator] = async conf => [];
-registerPlugin('router', 'void', voidPlugin);
+const validator = async conf => [];
+registerPlugin('router', 'void', voidPlugin, validator);