github-actions-cpu-cores

Uses os.availableParallelism (or os.cpus if availableParallelism is unavailable) to figure out how many logical cores are available on the runner.

name: Node CI

on:
  push:
    branches:
      - main
  pull_request:
    branches:
      - "**"

jobs:
  test:
    strategy:
      matrix:
        os: [ubuntu-latest, macOS-latest, windows-latest]
    runs-on: ${{ matrix.os }}

    steps:
      - name: Get number of CPU cores
        uses: SimenB/github-actions-cpu-cores@v3
        id: cpu-cores
      - name: run tests
        run: npx jest --max-workers ${{ steps.cpu-cores.outputs.count }}