NodeJS and npm: [npm ERR! cb.apply is not a function]

Lately I ran over this issue and I want to share with you how I got out of there: 

C:\>npm i npm -g

npm WARN npm npm does not support Node.js v14.17.0

npm WARN npm You should probably upgrade to a newer version of node as we

npm WARN npm can't make any promises that npm will work with this version.

npm WARN npm Supported releases of Node.js are the latest release of 6, 8, 9, 10, 11.

npm WARN npm You can find the latest version at https://nodejs.org/

npm ERR! cb.apply is not a function

npm ERR! A complete log of this run can be found in:

npm ERR!     %USERPROFILE%\AppData\Roaming\npm-cache\_logs\2021-05-30T14_58_58_367Z-debug.log

 It was after I installed a latest version of NodeJS. Command npm -v returned something like 6.*.*

We've tried to reinstall NodeJS.

We've tried to remove %USERPROFILE%\AppData\Roaming\npm-cache.

We've tried to uninstall NodeJS (together with npm).

We've tried to install NodeJS again.

We've tried to reinstall graceful-fs by npm i -g graceful-fs --force.

Nothing.... Same issue...

Finally we deleted both folders:

%USERPROFILE%\AppData\Roaming\npm
%USERPROFILE%\AppData\Roaming\npm-cache

Than we ran npm i npm -g again. And - voila! - it works.

I hope it can help someone...