According to Tim Neutkens co-author of Next.js, I did upgrade react from V16 to V17, but cannot figure out what causes this. However, I thought NextJS should automatically import ‘React’ for us. This is easy to fix by just adding import React from ‘react’ at the beginning of the file where reports this error. I also got another issue as the following: Unhandled Runtime Error Import CKEditor from clear that we have to use now because CKEditor is no longer the default import. The default import was removed since the package provides more than a single component now. The entry point of the package has changed. The onInit property was renamed to onReady and can be called multiple times (after the initialization and after the component is ready when an error occurred). There were no breaking changes between version 9 and 10. Usually, the major update (i.e., the first digit increment) includes some breaking change. I checked the package.json, there are two major updates that could be related to this: Check the render method of `CKEditorDemo`. You likely forgot to export your component from the file it's defined in, or you might have mixed up default and named imports. I got the following error when I tried CKEditor's demo page: Unhandled Runtime ErrorĮrror: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined. Today I was trying to fix the “auto-saving” bug and found that it had already broken. Recently I bumped several NPM packages for next-feathers, but I didn't have time to test it. I could not find any easy solution, but suggest doing this often and testing your app thoroughly.

However, updating packages without checking breaking changes is very dangerous. Running ' ncu -u' followed by ' npm install', we can have all our dependencies up to date.

Npm updates