Codewars-List Filtering Problem

ListFiltering.js

@@ -0,0 +1,36 @@
+/**
+* In this kata you will create
+* a function that takes a list of non-negative integers
+* and strings and returns a new list
+* with the strings filtered out.
+*
+* Example
+* filter_list([1,2,'a','b']) == [1,2]
+* filter_list([1,'a','b',0,15]) == [1,0,15]
+* filter_list([1,2,'aasf','1','123',123]) == [1,2,123]
+**/
+/**
+* without array's filter() method
+* traditional way of looping arrays,
+* faster than filter() method
+**/
+export default function filter_list_old(l) {
+// Return a new array with the strings filtered out
+  let filteredList = [];
+  if (Array.isArray(l)) {
+    for (let i = 0; i < l.length; i++) {
+      if (typeof l[i] === 'number') {
+        filteredList.push(l[i]);
+      }
+    }
+    return filteredList;
+  }
+}
+/**
+* using filter() method to return only number list
+**/
+function filter_list_es6(l) {
+  // Return a new array with the strings filtered out
+  return Array.isArray(l) && l.filter((val)=> (typeof val === 'number')) || undefined;
+}
+