From 745fdaafa4e261745ebe2d82547321f68644f735 Mon Sep 17 00:00:00 2001
From: Fenris Wolf <fenris@folksprak.org>
Date: Thu, 23 Oct 2025 13:19:39 +0200
Subject: [PATCH] [task-416]

---
 lib/plankton/plankton.d.ts |  3 +++
 lib/plankton/plankton.js   | 14 ++++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/plankton/plankton.d.ts b/lib/plankton/plankton.d.ts
index 30c6b9f..9da3c53 100644
--- a/lib/plankton/plankton.d.ts
+++ b/lib/plankton/plankton.d.ts
@@ -882,6 +882,9 @@ declare namespace lib_plankton.call {
     /**
      */
     export function sleep(seconds: float): Promise<void>;
+    /**
+     */
+    export function null_prop<type_value_from, type_value_to>(value_from: (null | type_value_from), function_: ((value: type_value_from) => type_value_to)): (null | type_value_to);
     export {};
 }
 declare namespace lib_plankton.file {
diff --git a/lib/plankton/plankton.js b/lib/plankton/plankton.js
index 8509b96..6a8b172 100644
--- a/lib/plankton/plankton.js
+++ b/lib/plankton/plankton.js
@@ -2043,6 +2043,16 @@ var lib_plankton;
             }));
         }
         call.sleep = sleep;
+        /**
+         */
+        function null_prop(value_from, function_) {
+            return ((value_from === null)
+                ?
+                    null
+                :
+                    function_(value_from));
+        }
+        call.null_prop = null_prop;
     })(call = lib_plankton.call || (lib_plankton.call = {}));
 })(lib_plankton || (lib_plankton = {}));
 /*
@@ -3792,10 +3802,10 @@ var lib_plankton;
             options = Object.assign({
                 "compare_value": instance_compare
             }, options);
-            if (is_empty(list)) {
+            /*if (is_empty<type_element>(list)) {
                 throw (new Error("the max-arg of an empty list is not defined"));
             }
-            else {
+            else */ {
                 return (list
                     .reduce(function (result, element, index) {
                     var value = target_function(element);