name: matrix
on: push

jobs:
  build:
    runs-on: ${{ matrix.os }}
    steps:
      - run: echo ${NODE_VERSION} | grep 4
        env:
          NODE_VERSION: ${{ matrix.node }}
    strategy:
      matrix:
        os: [ubuntu-18.04, macos-latest]
        node: [4, 6, 8, 10]