fixed a code based on mentor feedback ( wrote additional filter using && )

Author: Abduhasen

Sprint-1/fix/median.js

@@ -9,7 +9,9 @@ function calculateMedian(list) {
   if (!Array.isArray(list)) {
     return null;
   }
-  filteredList = list.filter((item) => typeof item === "number");
+  const filteredList = list.filter(
+    (item) => typeof item === "number" && !Number.isNaN(item)
+  );
   if (filteredList.length === 0) {
     return null;
   }

Sprint-1/implement/sum.js

@@ -2,7 +2,9 @@ function sum(elements) {
   if (elements.length === 0) {
     return 0;
   }
-  const number = elements.filter((value) => typeof value === "number");
+  const number = elements.filter(
+    (value) => typeof value === "number" && !Number.isNaN(value)
+  );
   if (number.length === 0) {
     return undefined;
   }