diff --git a/src/digicode.js b/src/digicode.js
index b13dc06..6254676 100644
--- a/src/digicode.js
+++ b/src/digicode.js
@@ -8,6 +8,9 @@ const display = /** @type {HTMLDivElement} */ (document.getElementById('display'
 const light = /** @type {HTMLDivElement} */ (document.getElementById('light'));
 const keypad = /** @type {HTMLDivElement} */ (document.getElementById('keypad'));
 
+/** @type {number|null} */
+let taskId = null;
+
 /**
  * @param {number} len
  * @returns {string}
@@ -30,6 +33,10 @@ function resetCode() {
  * @param {number} digit
  */
 function composeDigit(digit) {
+  if (taskId !== null) {
+    clearTimeout(taskId);
+    taskId = null;
+  }
   builder += digit.toString();
   display.innerText = builder + '_'.repeat(CODE.length - builder.length);
   light.classList.remove(IS_SUCCESS, IS_ERROR);
@@ -37,7 +44,7 @@ function composeDigit(digit) {
     light.classList.add(IS_SUCCESS);
   } else {
     light.classList.add(IS_ERROR);
-    setTimeout(resetCode, DELAY);
+    taskId = setTimeout(resetCode, DELAY);
   }
 }