make nvm node

Today I launched on a new project and there was a specific Node version required, specified (strangely) in package.json. I’ve expected it to be in .nvmrc, but never mind, I had to get it working, and I wanted it working with make, as I do for every new project.

I create a new Makefile where I usually have a start task to start whatever service I need for the app. For a Rails app, it’s have something like this:

start:
  bundle exec rais s

With a Node app though, one that requires a specific version of Node, as in this specific case, I needed to run something like this:

nvm exec 9.8.0 yarn start

…which, in a Makefile wouldn’t work because the commands are run in a new shell, and NVM is implemented as Bash functions, so nvm can’t be called from a Makefile. It’s quite easy to google the nvm GitHub issue on that: #1446, which recommends this:

bash -l -c 'nvm exec $(NODE_VERSION) yarn'

OK, but if you have more than one task, then this repetition becomes unacceptable, especially if you have to have a specific Node version, so I wrote a make function to hold the common parts:

define yarn
  $(eval npm_script_name=$(1))
  $(eval node_version=$(shell jq -r .engines.node package.json))

  bash -l -c "nvm exec $(node_version) yarn $(npm_script_name)"
endef

…and now, to call the "start" NPM scrip, I say:

start:
  $(call yarn, start)

…and, similarly for the other things that I want to make:

setup:
  $(call yarn, setup)

clean:
  $(call yarn, clean)

test:
  $(call yarn, test)

Neat! Now I can use my muscle memory to launch the server, or the tests, or whatever else I need. 🤓