добавляет тренировочные функции

index.html

@@ -234,5 +234,6 @@ <h2 class="data-error__title">Не удалось загрузить данны
       </section>
     </template>
 
+  <script src="/js/functions.js"></script>
 </body>
 </html>

js/functions.js

@@ -0,0 +1,24 @@
+function isLesserOrEqual(string, maxLength) {
+  return string.length <= maxLength;
+}
+
+function isPalindrome(string) {
+  let normalizedString = string.replaceAll(" ", "").toLowerCase();
+  let reversedString = normalizedString.split("").reverse().join("");
+
+  return normalizedString === reversedString;
+}
+
+function toPositiveNumber(string) {
+  let normalizedString = string.toString().replaceAll(" ", "");
+  let result = "";
+
+  for (let i = 0; i < normalizedString.length; i++) {
+    if(!isNaN(Number(normalizedString[i]))) {
+      result += normalizedString[i];
+    }
+  }
+
+  return parseInt(result);
+}
+