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javascriptuserscriptstampermonkey

SetimeOut interval fails with "Cannot convert undefined or null to object"

I'm getting into user scripting with tampermonkey and can't get through this error, any help would be appreciated.

I detect keys fine, space key triggers this function who will repeat itself as long as the key remains in the down position. The console writes the output normally for 30 seconds more or less and then there's a TypeError.

As per reputation-restriction, here's a screenshot:

User-Script:

// ==UserScript==
// @name         TEST STUFF--------------------
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @run-at         document-start
// @include        http://*
// @include        https://*
// @grant        none
// ==/UserScript==

( function()
{
    'use strict';
    window.addEventListener ( "keydown", CaptureKeyPress );
    window.addEventListener ( "keyup", CaptureKeyPress );
    var Hotkeys =
    {
        perform: 32
    };
    var HotkeyToggle = false;
    function CaptureKeyPress ( a )
    {
        if ( a.keyCode == Hotkeys.perform )
        {
            a.preventDefault();
            a.stopPropagation();
            a.cancelBubble = true;
            a.stopImmediatePropagation();

            if ( a.type == "keydown" && !HotkeyToggle )
            {
                console.clear();
                HotkeyToggle = true;
                perform();
            }

            if ( a.type == "keyup" && HotkeyToggle )
            {
                HotkeyToggle = false;
            }
        }
    }
    function perform()
    {
        if(HotkeyToggle == false) // exit
        {
            return 0
        }
        //do stuff...

        console.info("working...");
        if(HotkeyToggle == true) // continue after everything completes
        {
            setTimeout(() => {
                perform()
            }, 280);
            return 0
        }
        return 1
    }
} ) ();
Solution

  • This is either a TamperMonkey-specific issue, or a new security policy/bug in Chrome itself - I've ran into the same thing and caught it in the debugger, and none of the arguments are null/undefined; setTimeout is not overriden.

    Edit: A shared trait between the userscript in question and the one that I was debugging is the "recursive" use of setTimeout. I changed it to be a setInterval instead, and that seems to have fixed it in my case. enter image description here