median function updated according to requests

Author: mervereis

Sprint-1/fix/median.js

@@ -5,10 +5,34 @@
 // Hint: Please consider scenarios when 'list' doesn't have numbers (the function is expected to return null)
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
+// function calculateMedian(list) {
+//   const middleIndex = Math.floor(list.length / 2);
+//   const median = list.splice(middleIndex, 1)[0];
+//   return median;
+// }
+
+// module.exports = calculateMedian;
+
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  const numbers = list.filter((item) => typeof item === "number");
+
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  numbers.sort((a, b) => a - b);
+
+  const middle = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 === 0) {
+    return (numbers[middle - 1] + numbers[middle]) / 2;
+  }
+
+  return numbers[middle];
 }
 
 module.exports = calculateMedian;