fix(utils): handle edge cases in scroll percentage calculation #432

- Add checks for NaN, negative, and infinite values
- Ensure percentage is capped at 100%
- Improve reliability of scroll progress indicator

Co-Authored-By: xzadudu179 <129601567+xzadudu179@users.noreply.github.com>

source/js/utils.js

@@ -83,7 +83,19 @@ export default function initUtils() {
     },
 
     calculatePercentage(scrollTop, scrollHeight, clientHeight) {
-      return Math.round((scrollTop / (scrollHeight - clientHeight)) * 100);
+      let percentageValue = Math.round(
+        (scrollTop / (scrollHeight - clientHeight)) * 100,
+      );
+      if (
+        isNaN(percentageValue) ||
+        percentageValue < 0 ||
+        !isFinite(percentageValue)
+      ) {
+        percentageValue = 0;
+      } else if (percentageValue > 100) {
+        percentageValue = 100;
+      }
+      return percentageValue;
     },
 
     // register window scroll event