add dev

src/script.js

@@ -127,7 +127,6 @@ const getExample = () => {
         default:
             return isPlusMinusKind ? getMinusExample() : getDivisionExample();
     }
-
 };
 
 export const getDifficultyById = id => {
@@ -323,3 +322,13 @@ resetButton.addEventListener(EVENTS.CLICK, () => {
 });
 
 renderPage();
+
+const markDev = () => {
+    if (['localhost', 'dev'].some(v => location.href.includes(v))) {
+        const marker = document.getElementById('dev-marker');
+
+        marker.innerText = 'DEVELOP';
+    }
+};
+
+markDev();