Marty Penner

February 25 2020 ~ 3 min read

Using NVM to enforce node versions

At work, we previously used docker to give us a common node version by running every node and npm command through a wrapper script. This meant we wouldn’t run into strange gotchas between different versions of node and npm. But it also created more problems:

  • We couldn’t use different node versions per package. This means we had to find the lowest common denominator among all packages, so we were stuck on an older, slower version with fewer features.
  • We couldn’t debug node scripts the usual way because of the docker proxy.
  • Running e2e tests through a real browser required installing and configuring XQuartz, which was really wonky and not easy to train people on.
  • Performance was really bad. People were waiting many minutes for basic builds to finish.
  • Ctrl + C didn’t always work because of terminal shenanigans between docker and the host, so you could end up with hanging processes.
  • Watch/live-reload scripts didn’t work sometimes for reasons I don’t understand, meaning they had to run a full build for every change.
  • Other weird stuff I can’t remember right now.

Tools like nvm were made to deal with stuff like this, so why not use it? By modifying the previous wrapper script, but adding .nvmrc files to each package, the wrapper can ensure that nvm installs the needed node version before running. It also avoids polluting your shell, so your active node version doesn’t change simply because you ran npm i inside of a package. Works like a charm!

I also investigated volta, but it simply isn’t ready for me to use yet, primarily because it doesn’t allow installing “global” npm packages yet.

Here’s the full code the wrapper script:

#!/usr/bin/env bash

# This file mainly exists to be a facade for our watch/build/install scripts. By
# providing a thin layer on top, we can theoretically change out the underlying
# implementation without having to change our workflow too much.
# As of the time of this writing, we're enforcing the desired node and npm
# versions within each package by using `.nvmrc`.

# Fail fast
set -euo pipefail

# Set up nvm
. "$NVM_DIR/"
nvm install


case "$COMMAND" in
  # Expose npx directly to do whatever we need
    npx "${@:2}"
  # Expose npm directly to do whatever we need
    npm "${@:2}"
  # Expose node directly to do whatever we need
    node "${@:2}"
  # Remove all node_modules and bower components inside all packages
    find . -type d -iname node_modules -maxdepth 3 -exec rm -rf {} +
    find . -type d -iname bower_components -maxdepth 3 -exec rm -rf {} +

    echo "That command doesn't exist."
    exit 1

Headshot of Marty Penner

Hi, I'm Marty. I'm a software developer based in London, Ontario. You can follow me on Twitter or see some of my work on GitHub.