[solution to 4.3] Fix nth to handle the end of a list

marijnh · marijnh · commit 438df66c8759 · 2014-10-26T22:38:16.000+01:00
diff --git a/code/solutions/04_3_a_list.js b/code/solutions/04_3_a_list.js
@@ -17,7 +17,9 @@ function prepend(value, list) {
 }
 
 function nth(list, n) {
-  if (n == 0)
+  if (!list)
+    return undefined;
+  else if (n == 0)
     return list.value;
   else
     return nth(list.rest, n - 1);
