diff --git a/index.d.ts b/index.d.ts
index bd56b54..79724a2 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -27,7 +27,7 @@ declare class Router {
      * @protected
      * @type {boolean}
      */
-    protected debugMode: boolean
+    protected debugMode: boolean = false
     /**
      * CORS Config
      *
@@ -186,9 +186,9 @@ declare class Router {
     /**
      * Debug Mode
      * 
-     * @param {boolean} state Whether to turn on or off debug mode (default: true)
+     * @param {boolean} [state=true] Whether to turn on or off debug mode (default: true)
      */
-    debug(state: boolean): void
+    debug(state?: boolean): void
     /**
      * Enable CORS support
      *
diff --git a/index.js b/index.js
index 8454d75..c7d51d1 100644
--- a/index.js
+++ b/index.js
@@ -221,7 +221,7 @@ class Router {
     /**
      * Debug Mode
      * 
-     * @param {boolean} state Whether to turn on or off debug mode (default: true)
+     * @param {boolean} [state=true] Whether to turn on or off debug mode (default: true)
      */
     debug(state = true) {
         this.debugMode = state