Change the map function so that when the result.get() is undefined, we set it to the empty array (#1169)

ubik2 · web-flow · commit afa20acf181f · 2025-05-22T10:07:39.000-07:00
* Change the map function so that when the result.get() is undefined, we set it to the empty array. This prevents the subsequent read of length from failing.

* Move this check out of the list check
The list check will get some extra code that we don't want to run just because result.get() is undefind.
diff --git a/packages/runner/src/builtins/map.ts b/packages/runner/src/builtins/map.ts
@@ -60,6 +60,10 @@ export function map(
   return (log: ReactivityLog) => {
     let { list, op } = inputsCell.getAsQueryResult([], log);
 
+    // If the result's value is undefined, set it to the empty array.
+    if (result.get() === undefined) {
+      result.setAtPath([], [], log);
+    }
     // If the list is undefined it means the input isn't available yet.
     // Correspondingly, the result should be []. TODO: Maybe it's important to
     // distinguish empty inputs from undefined inputs?
