You are heading in the right direction but I fear you are not seeing the whole picture.
"Don't use sudo" does not combine with "use the fuck" because the fuck uses sudo. So really, you shouldn't be using either.
The proper way to fix permissions problems with npm is to create an ~/.npmrc with a prefix to $home
https://docs.npmjs.com/files/npmrc
You are heading in the right direction but I fear you are not seeing the whole picture.
"Don't use sudo" does not combine with "use the fuck" because the fuck uses sudo. So really, you shouldn't be using either.
The proper way to fix permissions problems with npm is to create an ~/.npmrc with a prefix to $home
https://docs.npmjs.com/files/npmrc