Provide a output for the selected Node.js version

It would be great if there could be an output that tells which exact version of Node.js was installed.

An example use case for this is cacheing node_modules, which is only valid for the same OS + Node.js version + package-lock combination:

name: Node CI

on:
  pull_request:
    branches:
    - master

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - name: Setup Node.js
      id: setup-node
      uses: actions/setup-node@v1
      with:
        node-version: 12.15.0

    - name: Cache dependencies
      id: cache-node-modules
      uses: actions/cache@v1
      with:
        path: node_modules
        key: ${{ runner.os }}-node-${{ steps.setup-node.outputs.node-version }}-modules-${{ hashFiles('package-lock.json') }}

    - name: Install dependencies
      run: npm ci
      if: steps.cache-node-modules.outputs.cache-hit != 'true'

    - name: Tets
      run: npm test

[panva]

#173 implements this.

[rdmurphy]

@simondotm The devil is in the details of how you’re trying to use the Node version so that may be good enough in some cases, but using strategy.matrix will only give you the string of the currently active matrix value. What we’re after here is the exact Node version that was installed as an output.

I’ll again note that setup-python already does this. Why setup-node doesn’t do the same is baffling.