added default timeout to function node (#1)

* added default timeout to function node

* added unit test to support defaultFunctionTimeout

packages/node_modules/node-red/settings.js

@@ -473,6 +473,7 @@ module.exports = {
  *  - fileWorkingDirectory
  *  - functionGlobalContext
  *  - functionExternalModules
+ *  - defaultFunctionTimeout
  *  - functionTimeout
  *  - nodeMessageBufferMaxLength
  *  - ui (for use with Node-RED Dashboard)
@@ -499,8 +500,30 @@ module.exports = {
     /** Allow the Function node to load additional npm modules directly */
     functionExternalModules: true,
 
+
+    /**
+     * Default function timeout (in seconds) for the Function node. 
+     * A value of 0 indicates no timeout is applied, meaning the function can run indefinitely.
+     * 
+     * The default function timeout is designed to prevent blocking code in function nodes, 
+     * which could otherwise lead to a stalled or unresponsive main thread. For example, 
+     * the following code would block the event loop indefinitely:
+     * 
+     *     `while(1) {}` 
+     * 
+     * By specifying a `defaultFunctionTimeout`, such scenarios can be mitigated, 
+     * ensuring that long-running or infinite loops are terminated automatically after 
+     * the specified timeout duration.
+     * 
+     * Note: If both `defaultFunctionTimeout` and `functionTimeout` are defined in the 
+     * settings file, `functionTimeout` takes precedence, providing a more granular 
+     * control for individual function nodes.
+     */
+
+    defaultFunctionTimeout: 5,
+
     /** Default timeout, in seconds, for the Function node. 0 means no timeout is applied */
-    functionTimeout: 0,
+    functionTimeout: 2,
 
     /** The following property can be used to set predefined values in Global Context.
      * This allows extra node modules to be made available with in Function node.