Skip to content
Nolapse Nolapse Docs

Tutorial: Node.js Express API

What This Tutorial Will Cover

Section titled “What This Tutorial Will Cover”

When Node.js support lands, this tutorial will walk through:

  1. Creating a minimal Express HTTP API with two routes (GET /health and GET /greet)
  2. Writing Jest tests with --coverage to generate a coverage/coverage-summary.json report
  3. Running nolapse init --repo . --lang nodejs to create the baseline
  4. Simulating a coverage regression by removing a test
  5. Running nolapse run --repo . --lang nodejs and seeing it exit 1
  6. Adding a GitHub Actions workflow that gates PRs on coverage

Expected Project Structure

Section titled “Expected Project Structure”
hello-express/
├── src/
│   ├── handler.js
│   └── handler.test.js
├── package.json
├── jest.config.js
├── .audit/
│   └── coverage/
│       └── baseline.md
└── nolapse.yaml

Expected Commands (Once Available)

Section titled “Expected Commands (Once Available)”

Initialise

Section titled “Initialise”
Terminal window
nolapse init --repo . --lang nodejs

Run a check

Section titled “Run a check”
Terminal window
nolapse run --repo . --lang nodejs

GitHub Actions workflow

Section titled “GitHub Actions workflow”
name: Coverage check


on:
  pull_request:


jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0


      - name: Set up Node
        uses: actions/setup-node@v4
        with:
          node-version: "20"


      - name: Install dependencies
        run: npm ci


      - name: Run nolapse
        uses: nolapse/nolapse-action@v1
        with:
          repo-token: ${{ secrets.GITHUB_TOKEN }}
          lang: nodejs
          warn-threshold: "0.5"
          fail-threshold: "1.0"

Coverage Report Format

Section titled “Coverage Report Format”

nolapse will read Jest’s coverage/coverage-summary.json format. To generate it, Jest must be configured with:

{
  "coverageReporters": ["json-summary"]
}

Or in jest.config.js:

module.exports = {
  coverageReporters: ["json-summary", "text"],
};

Get Notified

Section titled “Get Notified”

Watch the nolapse changelog for the Node.js runner release. Once available, this tutorial will be updated with full working commands and example output.

See Also

Section titled “See Also”