NPM - Some packages could not be installed

Question

I'm trying to install npm (package manager for node.js developers).

sudo apt-get install npm

But there seems to be a problem with installation:

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 npm : Depends: nodejs but it is not going to be installed
       Depends: node-abbrev (>= 1.0.4) but it is not going to be installed
       Depends: node-ansi but it is not going to be installed
       Depends: node-archy but it is not going to be installed
       Depends: node-block-stream but it is not going to be installed
       Depends: node-fstream (>= 0.1.22) but it is not going to be installed
       Depends: node-fstream-ignore but it is not going to be installed
       Depends: node-github-url-from-git but it is not going to be installed
       Depends: node-glob (>= 3.1.21) but it is not going to be installed
       Depends: node-graceful-fs (>= 2.0.0) but it is not going to be installed
       Depends: node-inherits but it is not going to be installed
       Depends: node-ini (>= 1.1.0) but it is not going to be installed
       Depends: node-lockfile but it is not going to be installed
       Depends: node-lru-cache (>= 2.3.0) but it is not going to be installed
       Depends: node-minimatch (>= 0.2.11) but it is not going to be installed
       Depends: node-mkdirp (>= 0.3.3) but it is not going to be installed
       Depends: node-gyp (>= 0.10.9) but it is not going to be installed
       Depends: node-nopt (>= 2.1.1) but it is not going to be installed
       Depends: node-npmlog but it is not going to be installed
       Depends: node-once but it is not going to be installed
       Depends: node-osenv but it is not going to be installed
       Depends: node-read but it is not going to be installed
       Depends: node-read-package-json (>= 1.1.0) but it is not going to be installed
       Depends: node-request (>= 2.25.0) but it is not going to be installed
       Depends: node-retry but it is not going to be installed
       Depends: node-rimraf (>= 2.2.2) but it is not going to be installed
       Depends: node-semver (>= 2.1.0) but it is not going to be installed
       Depends: node-sha but it is not going to be installed
       Depends: node-slide but it is not going to be installed
       Depends: node-tar (>= 0.1.18) but it is not going to be installed
       Depends: node-which but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

What should I do to fix this problem?

My OS: Ubuntu 14.04 LTS

Answer 1

Straight from https://nodesource.com/blog/nodejs-v012-iojs-and-the-nodesource-linux-repositories.

curl -sL https://deb.nodesource.com/setup_0.12 | sudo bash -

sudo apt-get install -y nodejs

Answer 2

Here is how to install the current stable or the latest versions of node and npm on Ubuntu. First step is to install the packages from the Ubuntu's repository:

sudo apt update
sudo apt install -y nodejs npm

The versions within the Ubuntu's repository are relatively old. You can check them by node -v and nmp -v. To get the latest versions we can use the n package that should be installed globally by npm.

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

Now you can check node -v and nmp -v again. Note you may need to log-out and log-in to the shell session, or open a new terminal, to see the correct new version.

Note n stable will install the newest stable version. In order to get the latest (beta) version use:

sudo n latest

By the n package you can easily switch between the different versions and manage them.