Develop Reference

Issue with Google Tag Manager implementation. "Uncaught TypeError: Wb.set is not a function"

Recently I started having Issues with the Google Tag Manager.
I can't track it to a Tag or a Trigger (activated and deactivated individually to check).
The error started occurring this week (no updates were made to the system or template). I noticed when testing the implementation of a new Tag in GTM. That shortly worked but then this error message started showing in the console. Removing the new Tag didn't change the situation and since the code worked for a while (some 30minutes) I don't expect a direct relationship between the new tag and the error.
All I have is the console in the frontend that shows the following error message:
Uncaught TypeError: Wb.set is not a function
The error stems from this file:
https://www.googletagmanager.com/gtm.js?id=GTM-XXXXXXX
Wb is started as a Map just a few steps earlier:
Wb=new Map(Vb.h.F);
Wb.set("style",{ya:4});
The GTM Script is copied and pasted from the GTM-Admin without any change made to it and is included in the header.php file of the Wordpress template. I tried copying it again and replacing the script that was in the header.php previously but the result was the same.
If looking at the actual error message in the console helps, the issue can be seen on the following URL:
https://www.bindella.ch
Any help in solving this or at least pointer to where to go look for errors would be very much appreciated.
Thanks

Very interesting, and yes, you're right, the error in the minified code makes no sense:
Let's try something different. First, just export your GTM container (the workspace that is synced with prod/live) as a JSON file in Admin section.
Open the file, look for something like set("style" See if you can find that Wb. Well, don't expect it to be Wb. I guess GTM minifies the code. It may be some weird chat bot, or something like that. From there, you'll be able to find the tag or variable that causes the issue.
I didn't look too deep into it, but that part of code looks sophisticated enough to be a part of the core container code. Actually, we can check it right here, on SO cuz it uses GTM too, let's do that.
Yes, SO has identical code. Looks like it's indeed core GTM. Well, there's a tiny probability that when you built the prod library last time, GTM had an issue and it deployed an artefact.
Try making a new workspace, make a nonsensical change in it and publish it to production. See if it lets you publish. Then see if that fixes the issue.
Now, if it doesn't then the next thing I'd try is trying to re-importing the exported JSON, forcing GTM compare the import to what's there and find differences.
Now if that shows no issues, then I would make a brand new container, load the config in it and try replacing the gtm loading script to see if the error still happens. It sounds like you can do that. If you can't, look a plugin like redirector to redirect the request to a different container.
Still the error with the new container? How about if you load a completely empty container? Got any errors?
There's a very slim chance that your front-end deploys one of a few vars GTM uses too, thus conflicting with your GTM. But it's very unlikely. Why would you use something like google_tag_manager or google_tag_data in the global scope...
If nothing helps and only the empty container doesn't give errors, then... well, then make a list of all tags firing along that error and start disabling them one by one. Or use breakpoints to narrow it down to the tag/library that causes it.

Opencart - cant change js files. adding kind of reddots at the end

firstly very sorry, I cant find out what the real problem is.
I ll try to explain.
My client given code which is developed using opencart and nitropack.
he includes common.js in header, it is basic js file with some ajax calls, UI events etc which has 1297 lines(no formating in code, lots of blank spaces, blank lines etc).
my real problem is, when I made any changes in this file,
the browser console is throwing error invalid or unexpected token.
I checked the common.js file in browser console, seeing that some kind of reddots added at last of the file. I just added a alert() at the begining of file. nothing else.
very sorry, dont know how to explain more detaily.
This is the first time I have seen this kind of issue.
when I removed the alert(), the error gone.

Syntax check passes but uncaught SyntaxError: Unexpected identifier

Guys what else could be wrong when jshint, esprima all passes the code but chrome throws this error ? I am having a hard time figuring out.
P.S : Sorry I can't really share the code as I am not supposed to and I have to share the whole app code.

If you can't share the code, it will be hard for anyone to tell you what is wrong.
One thing you can do is simplify your code down to a concise test case, using the "divide and conquer" technique. Just start taking out big chunks of code, and keep repeating until one of the following happens:
The error goes away. This means the problem was in the last chunk of code you deleted. Put that code back in and take out only part of it and test again. Repeat this as needed.
Some other error crops up that wasn't there originally. Put back the last deleted chunk and either try deleting only a part of it, or deleting something else.
The error remains, but now there is so little code left that you will either see what the problem is, or else you won't have a problem posting it here for help. Once you have it down to a minimal test case like this, you can start renaming variables and functions so that it no longer reveals any company secrets.

JSCOMPILER_PRESERVE after compiling javascript with KJSCompiler

After compiling my JavaScript source with KJSCompiler (https://github.com/knyga/kjscompiler) I get this weird function wrapped around my code. If I try to include it in my live source code I get this error in the console "Uncaught ReferenceError: JSCOMPILER_PRESERVE is not defined ".
I thought that this problem occurred because I didn't add the "wrapper" in the JSON file of kjscompiler. After trying that it still occurs.
Does anyone have an idea how to fix this?

I came across this when using Closure Compiler directly via the Java API.
It seems to be caused by running the compiler in checks-only mode but with protect hidden side effects enabled. The late pass to remove protection of hidden side effects is skipped in checks-only mode.
I'm not sure about KJSCompiler specifically, but it might help to look at changing the compilation level to SIMPLE or ADVANCED, and/or how you might be able to control what checks and optimisations run to KJSCompiler, e.g. turning off CompilerOptions.protectHiddenSideEffects.
See https://github.com/google/closure-compiler/issues/1875

In addition to Steve S's answer:
set protectHiddenSideEffects after setting optimization level, as options.setProtectHiddenSideEffects(false); didn't work for me for GCC version v20180204 if I set it before setting CompilationLevel.
CompilationLevel.ADVANCED_OPTIMIZATIONS.setOptionsForCompilationLevel(compilerOptions);
//To remove JSCOMPILER_PRESERVE error: https://github.com/google/closure-compiler/issues/1875
compilerOptions.setProtectHiddenSideEffects(false);

How to get PHP / JavaScript error popups to appear styled properly?

This is a beginner's question -- surely already answered but I don't know how to find it:
When a coding/system error message pops up during processing of a PHP script or possibly JavaScript, its title is usually "The page at localhost [or other URL] says:". Its content usually includes a load of non-rendered HTML code (<b>, <br>, etc), a long reference to a PHP manual, an actual error message, and a reference to where the error occurred. Because the HTML is being ignored, the whole dialog is hard to read.
How can I get such windows to appear styled properly, as surely intended by the "folks at PHP or JavaScript", or at least appear in simple text with line breaks?
Please note: It is not an error message that I am intending to pop up in response to any user action; I don't know what is causing the message. Also, I'm not seeking advice on how to make user-friendly software or on how to do continuous development-and-delivery

How can I get such windows to appear styled properly, as intended?
I don't know which window you are talking about, however from the rest of your description it sounds to me that you want to turn HTML error off so to get the plain text version of the error messages.
PHP has a setting for that Docs:
html_errors boolean
Turn off HTML tags in error messages. The new format for HTML errors produces clickable messages that direct the user to a page describing the error or function in causing the error. These references are affected by docref_root and docref_ext.
So all you need to do is to turn if off, either in your php.ini:
html_errors = 0
Or within your code:
<?php
ini_set('html_errors', 0);
You might also be interested in:
How to get useful error messages in PHP?

Never have your errors show up in a production website!!
If you're talking about dealing with errors while you're developing, then check out the Whoops library. It'll give you everything you want, plus much more.
Here's a quote from their homepage:
whoops is a nice little library that helps you develop and maintain your projects better, by helping you deal with errors and exceptions in a less painful way.
Check out their demo here. You can click on the left side to go through the stack. Really cool.