diff --git a/app/main.js b/app/main.js
index 8f1d804..2ea92c1 100644
--- a/app/main.js
+++ b/app/main.js
@@ -7,6 +7,6 @@ const version = import.meta.env.MODE === 'development'
 
 const game = new mnswpr('app', version, {
   levelChanged: () => console.log('[hook]: level reset'),
-  gameDone: (game) => console.log('[hook] game done', game)
+  gameDone: (game) => console.log('[hook]: game done', game)
 })
 game.initialize()
\ No newline at end of file
diff --git a/lib/mnswpr.js b/lib/mnswpr.js
index d1a1746..4122476 100644
--- a/lib/mnswpr.js
+++ b/lib/mnswpr.js
@@ -21,16 +21,23 @@ const PC_BUSY_DELAY = 500
  * @param {String} appId 
  * @param {String} version
  * @param {{
- * levelChanged: () => {},
- * gameDone: (game: any) => {}
- * }} hooks
+ * levelChanged: () => void,
+ * gameDone: (game: any) => void
+ * } | undefined } hooks
  */
-const Minesweeper = function(appId, version, hooks) {
+const Minesweeper = function(appId, version, hooks = undefined) {
   const _this = this
   const storageService = new StorageService()
   const timerService = new TimerService()
   const loggerService = new LoggerService()
 
+  if (!hooks) {
+    hooks = {
+      levelChanged: () => {},
+      gameDone: () => {}
+    }
+  }
+
   let grid = document.createElement('table')
   grid.setAttribute('id', 'grid')
   let flagsDisplay = document.createElement('span')
@@ -219,7 +226,6 @@ const Minesweeper = function(appId, version, hooks) {
     if (initial)
       hooks.levelChanged()
 
-
     timerService.initialize(timerDisplay)
     updateFlagsCountDisplay()
     addMines(setting.mines)