i've been forced to install node.js into my linux box in ubuntu by my boss and i could not find a really solution on how to do it. when i googled it everyone metioned something about PPA which i have no idea what i its, so this is the best and simple way i was able to install nodejs.

Update Package Manager

$ sudo apt-get update

$ sudo apt-get upgrade

Install NodeJS

$ sudo apt-get install nodejs

$ node -v
v8.10.0

Install NPM

$ sudo apt-get install npm

$ npm -v
3.5.2

$ command -v npm
/usr/bin/npm

Now that we installed npm, we can update it with this command:

$ sudo npm install -g npm

confirm the latest version has been installed

$ /usr/local/bin/npm -v
6.10.2

$ npm -v
3.5.2
* NOTE npm still shows the old version? by why? - Because its hashed! to fix it, follow these commands, you can confirm this by executing the following command

$ command -v npm
/usr/bin/npm

$ type npm
npm is hashed (/usr/bin/npm)

Fix NPM

To fix this issue, all you have to do is send this shell command:

$ hash -d npm
NOTE: you will not get any output on this command, its normal so dont panic!

Confirm you've fixed npm with the latest version:

$ npm -v
6.10.2

$ command -v npm
/usr/local/bin/npm

Fix NodeJS

You are done with npm, its time to update nodeJs. To be able to update nodejs we will use n module from npm.

$ sudo npm cache clean -f
$ sudo npm install -g n

/usr/local/bin/n -> /usr/local/lib/node_modules/n/bin/n
+ [email protected]
added 1 package from 4 contributors in 0.514s

You have two options here, you can upgrade to the stable version (LTS) or the current version

Option 1 - Stable Version

$ sudo n stable
 installing : node-v10.16.0
       mkdir : /usr/local/n/versions/node/10.16.0
       fetch : https://nodejs.org/dist/v10.16.0/node-v10.16.0-linux-x64.tar.gz

Option 2 - Current Version

To upgrade to latest version (and not current stable) version, you can use

$ sudo n latest
  installing : node-v12.7.0
       mkdir : /usr/local/n/versions/node/12.7.0
   installed : v12.7.0

$ /usr/local/bin/node -v
v10.6.0

$ node -v
v8.10.0

Notice the difrences here, what we want is four our node to be v10 not v8. to fix this, you need to delete the hash

$ hash -d

$ node -v
v10.6.0

Now that the hash was removed, we can clearly see v10

I know this is alot of commands. I wish there was an easy way. If I find one, I will post it here.

Hope that help.

Resources:
https://askubuntu.com/questions/1036278/npm-is-incorrect-version-on-latest-ubuntu-18-04-installation
WORKS!! HOW TO UPDATE NODEJS IN UBUNTU:
https://askubuntu.com/questions/426750/how-can-i-update-my-nodejs-to-the-latest-version

[ERROR] ng has unexpectedly closed (exit code 127)
https://stackoverflow.com/questions/51569546/ionic-a-utility-cli-has-unexpectedly-closed