How can I fix NPM which always says unexpected token = - npm

Question

After my machine updated automatically, NPM is not working any more
OS: Ubuntu 20.04.3 LTS
npm -v: 8.1.4
node -v: v10.19.0
Every time I try to start something with NPM, it gives me the same error message:
*#*:~$ npm help
npm WARN npm npm does not support Node.js v10.19.0
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 You can find the latest version at https://nodejs.org/
npm ERR! Unexpected token =
npm ERR! A complete log of this run can be found in:
npm ERR! /home/*/.npm/_logs/2021-11-19T13_44_25_087Z-debug.log
The Error log contains the following:
0 verbose stack /usr/local/lib/node_modules/npm/lib/commands/help.js:16
30 verbose stack static description = 'Get help on npm'
30 verbose stack ^
30 verbose stack
30 verbose stack SyntaxError: Unexpected token =
30 verbose stack at Module._compile (internal/modules/cjs/loader.js:723:23)
30 verbose stack at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
30 verbose stack at Module.load (internal/modules/cjs/loader.js:653:32)
30 verbose stack at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
30 verbose stack at Function.Module._load (internal/modules/cjs/loader.js:585:3)
30 verbose stack at Module.require (internal/modules/cjs/loader.js:692:17)
30 verbose stack at require (internal/modules/cjs/helpers.js:25:18)
30 verbose stack at Npm.cmd (/usr/local/lib/node_modules/npm/lib/npm.js:97:18)
31 verbose cwd /home/*
32 verbose Linux 5.11.0-40-generic
33 verbose argv "/usr/bin/node" "/usr/local/bin/npm" "help"
34 verbose node v10.19.0
35 verbose npm v8.1.4
36 error Unexpected token =
37 verbose exit 1

Answer 1

I solved it like this:
Install nvm
sudo apt install curl
curl https://raw.githubusercontent.com/creationix/nvm/master/install.sh | bash
source ~/.profile
nvm install node
Source

Answer 2

Upgrade your node version, you're using the newest npm version, and it doesn't support old versions of node
Since you're on ubuntu i recommend you to use nvm
sudo apt-get install nvm
nvm install 16
nvm use 16

Answer 3

npm is broken because it will ignore PATH, and it will ignore the calling runtime, instead it will use an arbitrary runtime.
sudo which node
/usr/local/bin/node
.
sudo /usr/local/bin/node --version
v17.1.0
.
sudo /usr/local/bin/node /usr/local/bin/npm install -g node#latest
...
npm ERR! npm WARN npm npm does not support Node.js v10.19.0
...
removing the distribution version might be a workaround.