Implement sum function to calculate the total of numeric values in an array, handling empty arrays and non-array inputs.

Author: ashaahmed7

Sprint-1/implement/sum.js

@@ -1,4 +1,22 @@
 function sum(elements) {
+  if (!Array.isArray(elements)) {
+    return null;
+  }
+  // Check if array is empty
+  if (elements.length === 0) {
+    return 0;
+  }
+  // Filter only numeric values
+  const numericElements = elements.filter((item) => typeof item === "number");
+  if (numericElements.length === 0) {
+    return -Infinity;
+  }
+  // Calculate the sum of numeric values
+  let total = 0;
+  for (let i = 0; i < numericElements.length; i++) {
+    total += numericElements[i];
+  }
+  return total;
 }
 
 module.exports = sum;