Support .nvmrc

It would be nice if setup-node understood an .nvmrc file (even if it does not use nvm under the hood, the idea is the node-version is just the contents of the file).

If GitHub Actions as a whole could read the contents of a file as part of an expression, I could do something like

uses: setup-node@v1
with:
  node-version: {{ contents(.nvmrc) }}

But I don’t know where to log that type of feature request!

Perhaps ‘.nvmrc’ could be used as a special placeholder, so that:

uses: setup-node@v1
with:
  node-version: '.nvmrc'

Instructs this action to read the contents and treat the contents as the desired version?

[mauriciabad]

If you got here from googling, let me tell you, that the newest and simplest way of reading the .nvmrc file and using it in actions/setup-node is with the node-version-file option:

  - name: Setup node
    uses: actions/setup-node@v3
    with:
      node-version-file: '.nvmrc'

[damccorm]

Sorry, had a lapse when I wrote this. Try changing your workflow to:

- name: Read .nvmrc
  run: echo "##[set-output name=NVMRC;]$(cat .nvmrc)"
  id: nvm

- name: Use Node.js (.nvmrc)
  uses: actions/setup-node@v1
  with:
    node-version: "${{ steps.nvm.outputs.NVMRC }}"

Env variables are scoped to a given step so they don’t automatically carry over, but we can use outputs instead.