more working

src/ytdl_sub/script/functions/conditional_functions.py

@@ -64,6 +64,6 @@ class ConditionalFunctions:
           otherwise returns ``else_arg``.
         """
         maybe_true_value = maybe_true_arg.value()
-        if bool(maybe_true_value):
+        if bool(maybe_true_value.value):
             return maybe_true_value
         return else_arg.value()

src/ytdl_sub/script/types/function.py

@@ -229,6 +229,8 @@ class BuiltInFunction(Function, BuiltInFunctionType):
 
         assert isinstance(lambda_array, Array)
 
+        if len(lambda_array.value) == 0:
+            return Array(value=[])
         if len(lambda_array.value) == 1:
             return lambda_array.value[0]
 

tests/unit/script/types/test_lambda_function.py

@@ -15,6 +15,11 @@ class TestLambdaFunction:
             {"%times_two": "{%mul($0, 2)}", "wip": "{%array_apply([1, 2, 3], %times_two)}"}
         ).resolve() == ScriptOutput({"wip": Array([Integer(2), Integer(4), Integer(6)])})
 
+    def test_lambda_with_custom_function_empty_input(self):
+        assert Script(
+            {"%times_two": "{%mul($0, 2)}", "wip": "{%array_apply([], %times_two)}"}
+        ).resolve() == ScriptOutput({"wip": Array([])})
+
     def test_conditional_lambda_with_custom_functions(self):
         assert Script(
             {