Node.js Version Installer

A command-line tool to make Node.js binaries available in CI environments.

Dependencies

OS	Will it work?
GNU/Linux	✅ Yes. Just ensure you have all the GNU software mentioned below.
macOS	⚠️ With some effort. The coreutils shipped with OS X do not work, but you can install the GNU versions using brew.
Windows	⚠️ With Bash for Windows, yes. We've successfully used nvi in Bash for Windows. It works out of the box.

In order to run, nvi assumes the following software is available:

• GNU coreutils
• Other GNU software: bash, grep, tar, tput, wget

These are available in many GNU/Linux distributions and certainly through their various package managers.

Can't I just use nvm?

We've used nvm for local Node.js development for a long time. It works very well on your local machine, where you tend to have long-running bash sessions and tend to frequently switch between Node.js versions. However, it has not been as painless to use in CI environments, where your bash sessions tend to be very brief and interspersed across machines, docker containers, and build jobs.

What causes this friction between CI environments and nvm? The answer is essentially: bash functions.

The way nvm makes its functionality available to the user is as a bash function by the same name. This bash function is loaded using your ~/.bashrc or ~/.bash_profile file, and it lives while your bash session does. In particular, nvm is not an executable file, it is not on your $PATH, and it is not a system-wide command.

The way most recent CI environments work is by letting you group several statements into a "job", "stage", or something similar, and then execute these jobs in fresh Docker containers based on a small set of common images. In this setup everything is running in its own containerized little world, and there is no guarantee that each step in a CI job is executed within a bash context. In our current CI, there is no such bash context, no .bashrc or .bash_profile is loaded, and it generally requires additional workarounds to make this happen.

Another approach: nvi

We really want to use containerized CI, so we considered how other dependencies are injected in our Docker containers, and how to do the same for our Node.js version installer. A common solution is to download an executable, put it on the path, and then build it into the image used by your CI. This is exactly what nvi strives to support.

Design criteria

nvi strives to:

1. Be a simple way to install Node.js versions in CI environments.
2. Let you install specific versions of executables for node and npm.
3. Let you place these node and npm executables on your $PATH.
4. Let you specify your desired Node.js version in package.json.

nvi avoids:

1. Providing its functionality as bash functions.
2. Providing more features than what CI needs.
3. Needing exotic dependencies. See the dependencies section.
4. Having more source code than what you can skim in a few minutes.

Usage

There is one major use case for nvi: install node and npm executables on your system. To facilitate this, nvi has a bunch of default options, each of which can be overridden independently if you disagree with them using CLI flags.

There are a number of paths used in downloading, extracting, and storing both the necessary JavaScript source and executables. See nvi --help.

If not told otherwise, nvi will attempt to read ./package.json to infer the right version of Node.js to install. You need to either override this default using --node-version or make sure your ./package.json file contains the following keys:

{
  "engines": {
    "node": "6.10.0"
  }
}

This will make nvi install version 6.10.0. Note that nvi just installs the executables. It's up to you to put them on the $PATH if necessary.

References

• nvi: https://github.com/DanskSupermarked/nvi
• nvm: https://github.com/creationix/nvm