Finished

Test Name	Status
empty	Pass
no nesting	Pass
flattens a nested array	Pass
flattens array with just integers present	Pass
5 level nesting	Pass
6 level nesting	Pass
undefined values are omitted from the final result	Pass
null values are omitted from the final result	Pass
consecutive null values at the front of the array are omitted from the final result	Pass
consecutive null values in the middle of the array are omitted from the final result	Pass
6 level nested array with null values	Pass
all values in nested array are null	Pass

  * @returns {any[]}
  */
 export const flatten = (arr) => {
+  throw new Error('Remove this line and implement the function');
+  // Edge Case: Handle null or undefined input
+  if (arr === null || arr === undefined) {
+    return [];
+  }
+  // Edge Case: Handle non-array input
+  if (!Array.isArray(arr)) {
+    return [];
+  }
+  const result = [];
+  for (let i = 0; i < arr.length; i++) {
+    const element = arr[i];
+    // Edge Case: Skip null or undefined elements
+    if (element === null || element === undefined) {
+      continue;
+    }
+    // Edge Case: Recursively flatten nested arrays
+    if (Array.isArray(element)) {
+      const flattened = flatten(element);
+      for (let j = 0; j < flattened.length; j++) {
+        result.push(flattened[j]);
+      }
+    } else {
+      result.push(element);
+    }
+  }
+  return result;
 };
+// Handled Edge Cases: null/undefined input, non-array input, null/undefined elements, nested arrays

Polyglot JavaScript - without test patch