How to install Node.js on Ubuntu 18.04

I installed npm without installing Node.js by executing:

$ sudo apt install npm

...but this installed its very old version:

$ npm --version
3.5.2

npm comes with Node.js and I wanted to install their latest version. After reading this Q&A thread I decided to use nvm.

$ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.11/install.sh | bash
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 12819  100 12819    0     0  34093      0 --:--:-- --:--:-- --:--:-- 34093
=> Downloading nvm from git to '/home/bojan/.nvm'
=> Cloning into '/home/bojan/.nvm'...
remote: Enumerating objects: 267, done.
remote: Counting objects: 100% (267/267), done.
remote: Compressing objects: 100% (242/242), done.
remote: Total 267 (delta 31), reused 86 (delta 15), pack-reused 0
Receiving objects: 100% (267/267), 119.47 KiB | 385.00 KiB/s, done.
Resolving deltas: 100% (31/31), done.
=> Compressing and cleaning up git repository
=> Appending nvm source string to /home/bojan/.bashrc
=> Appending bash_completion source string to /home/bojan/.bashrc
=> Close and reopen your terminal to start using nvm or run the following to use it now:

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm
[ -s "$NVM_DIR/bash_completion" ] && \. "$NVM_DIR/bash_completion"  # This loads nvm bash_completion

Here is the list of nvm options and arguments:

$ nvm -v

Node Version Manager

Note: <version> refers to any version-like string nvm understands. This includes:
  - full or partial version numbers, starting with an optional "v" (0.10, v0.1.2, v1)
  - default (built-in) aliases: node, stable, unstable, iojs, system
  - custom aliases you define with `nvm alias foo`

 Any options that produce colorized output should respect the `--no-colors` option.

Usage:
  nvm --help                                Show this message
  nvm --version                             Print out the installed version of nvm
  nvm install [-s] <version>                Download and install a <version>, [-s] from source. Uses .nvmrc if available
    --reinstall-packages-from=<version>     When installing, reinstall packages installed in <node|iojs|node version number>
    --lts                                   When installing, only select from LTS (long-term support) versions
    --lts=<LTS name>                        When installing, only select from versions for a specific LTS line
    --skip-default-packages                 When installing, skip the default-packages file if it exists
    --latest-npm                            After installing, attempt to upgrade to the latest working npm on the given node version
    --no-progress                           Disable the progress bar on any downloads
  nvm uninstall <version>                   Uninstall a version
  nvm uninstall --lts                       Uninstall using automatic LTS (long-term support) alias `lts/*`, if available.
  nvm uninstall --lts=<LTS name>            Uninstall using automatic alias for provided LTS line, if available.
  nvm use [--silent] <version>              Modify PATH to use <version>. Uses .nvmrc if available
    --lts                                   Uses automatic LTS (long-term support) alias `lts/*`, if available.
    --lts=<LTS name>                        Uses automatic alias for provided LTS line, if available.
  nvm exec [--silent] <version> [<command>] Run <command> on <version>. Uses .nvmrc if available
    --lts                                   Uses automatic LTS (long-term support) alias `lts/*`, if available.
    --lts=<LTS name>                        Uses automatic alias for provided LTS line, if available.
  nvm run [--silent] <version> [<args>]     Run `node` on <version> with <args> as arguments. Uses .nvmrc if available
    --lts                                   Uses automatic LTS (long-term support) alias `lts/*`, if available.
    --lts=<LTS name>                        Uses automatic alias for provided LTS line, if available.
  nvm current                               Display currently activated version of Node
  nvm ls                                    List installed versions
  nvm ls <version>                          List versions matching a given <version>
  nvm ls-remote                             List remote versions available for install
    --lts                                   When listing, only show LTS (long-term support) versions
  nvm ls-remote <version>                   List remote versions available for install, matching a given <version>
    --lts                                   When listing, only show LTS (long-term support) versions
    --lts=<LTS name>                        When listing, only show versions for a specific LTS line
  nvm version <version>                     Resolve the given description to a single local version
  nvm version-remote <version>              Resolve the given description to a single remote version
    --lts                                   When listing, only select from LTS (long-term support) versions
    --lts=<LTS name>                        When listing, only select from versions for a specific LTS line
  nvm deactivate                            Undo effects of `nvm` on current shell
  nvm alias [<pattern>]                     Show all aliases beginning with <pattern>
  nvm alias <name> <version>                Set an alias named <name> pointing to <version>
  nvm unalias <name>                        Deletes the alias named <name>
  nvm install-latest-npm                    Attempt to upgrade to the latest working `npm` on the current node version
  nvm reinstall-packages <version>          Reinstall global `npm` packages contained in <version> to current version
  nvm unload                                Unload `nvm` from shell
  nvm which [current | <version>]           Display path to installed node version. Uses .nvmrc if available
  nvm cache dir                             Display path to the cache directory for nvm
  nvm cache clear                           Empty cache directory for nvm

Example:
  nvm install 8.0.0                     Install a specific version number
  nvm use 8.0                           Use the latest available 8.0.x release
  nvm run 6.10.3 app.js                 Run app.js using node 6.10.3
  nvm exec 4.8.3 node app.js            Run `node app.js` with the PATH pointing to node 4.8.3
  nvm alias default 8.1.0               Set default node version on a shell
  nvm alias default node                Always default to the latest available node version on a shell

Note:
  to remove, delete, or uninstall nvm - just remove the `$NVM_DIR` folder (usually `~/.nvm`)


Let's now install the latest version of Node.js. To check which one is the latest, go here. At the time of writing it was 10.11.0. In a new terminal session do the following:

$ nvm install 10.11.0
Downloading and installing node v10.11.0...
Downloading https://nodejs.org/dist/v10.11.0/node-v10.11.0-linux-x64.tar.xz...
################################################################################################################# 100.0%
Computing checksum with sha256sum
Checksums matched!
Now using node v10.11.0 (npm v6.4.1)
Creating default alias: default -> 10.11.0 (-> v10.11.0)

Let's check the versions now:

$ node --version
v10.11.0

$ npm --version
6.4.1

Alternatively, if we don't care about the version but just want to install the latest stable version we can do:

$ node -v
v11.13.0

$ nvm install stable
Downloading and installing node v14.1.0...
Downloading https://nodejs.org/dist/v14.1.0/node-v14.1.0-linux-x64.tar.xz...
####################################################################################################################################################################### 100.0%
Computing checksum with sha256sum
Checksums matched!
Now using node v14.1.0 (npm v6.14.4)

$ node -v
v14.1.0

The version which is installed is indeed the latest stable albeit not the one recommended for most users:

References:

How to Update Node.js to Latest Version (Linux, Ubuntu, OSX, Others) - HostingAdvice.com