GitHub Actions Basics

# .github/workflows/hello.yml
name: Hello World

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  greet:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Print greeting
        run: echo "Hello from GitHub Actions!"

      - name: Show runner info
        run: |
          echo "OS: $RUNNER_OS"
          echo "Workspace: $GITHUB_WORKSPACE"
          node --version
          python3 --version

# Matrix build — test on multiple Node versions
jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [18, 20, 22]

    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm ci
      - run: npm test