[Fixed] Uncaught (in promise) Error: Illegal argument undefined at e.exports (content.js:33:95534) – Google-chrome

The Problem:

A user is encountering an error message "Uncaught (in promise) Error: Illegal argument undefined" while working on a MERN todo app in Chrome browser. The same error persists regardless of the page they are on, but it does not occur in other browsers. The user has compared their code with the instructor’s and found no differences. They are seeking assistance in resolving this issue.

The Solutions:

Solution 1: Disable Chrome Extensions

The error “Uncaught (in promise) Error: Illegal argument undefined at e.exports (content.js:33:95534)” is often caused by a Chrome extension interfering with the content.js script used by your MERN todo app. To resolve this issue, try the following:

1. Disable Suspicious Extensions:
   • Open Chrome and click on the Extensions icon (usually located in the top right corner, next to the profile picture).
   • Disable any extensions that you suspect might be causing the issue, especially those related to content modification or ad blocking.
2. Check for Updates:
   • Ensure that all your Chrome extensions are up to date. Outdated extensions can cause compatibility issues.
   • To update extensions, click on the Extensions icon, then select Manage extensions. Click the Update button next to any extensions that have updates available.
3. Disable All Extensions:
   • If the problem persists, try disabling all extensions temporarily to see if it resolves the issue.
   • To disable all extensions, go to the Extensions page, click the ⋮ menu icon in the top right corner, and select Disable all extensions.
4. Identify the Problematic Extension:
   • If disabling all extensions resolves the issue, re-enable them one by one to identify the one causing the problem.
   • Once you find the problematic extension, you can either keep it disabled or seek an alternative extension that doesn’t cause conflicts.