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In this guide, you’ll learn what Node.js is and how to set up, test, and run a simple “Hello World” application. We’ll also show you how to integrate this Node.js project into a custom GitHub Actions workflow for continuous integration.

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What Is Node.js?

Node.js is an open-source, cross-platform JavaScript runtime built on Chrome’s V8 engine. It enables you to run JavaScript on the server side, unifying your front-end and back-end development in a single language. Installing Node.js also provides npm (Node Package Manager) for managing your dependencies.
  • High performance with non-blocking I/O
  • Vast ecosystem via npm
  • Single language for client and server

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Prerequisites

Before you begin, ensure you have Node.js and npm installed on your machine. 
node -v    # e.g., v18.16.0
npm -v     # e.g., 9.8.1
Always verify that your CI/CD environment (like GitHub Actions) uses the same Node.js version as your local setup to avoid inconsistencies.

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Sample Project Structure

Below is a minimal Node.js project that returns “Hello World” from a /hello endpoint.
FilePurpose
package.jsonMetadata (name, version), dependencies, and script definitions
index.jsMain application file (defines server and routes)
test.jsSimple test suite to verify the logic in index.js

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Installing Dependencies

Install all required packages listed in package.json: 
npm install
On success, npm generates a node_modules directory containing your project’s dependencies.

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Running Your Tests

Run the test suite defined in test.js: 
npm test
Expected output: 
> [email protected] test
> node test.js

Testing is successful

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Starting the Application

Launch the server: 
npm start
You’ll see: 
> [email protected] start
> node index.js

App listening on port 3000
In another terminal or your browser, request the /hello endpoint: 
curl http://localhost:3000/hello
# Hello World!

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GitHub Actions Workflow

Automate your CI/CD pipeline by adding a workflow file at .github/workflows/ci.yml: 
name: Node.js CI

on: [push, pull_request]

jobs:
  build-and-test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [18.x]

    steps:
      - uses: actions/checkout@v3

      - name: Use Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.node-version }}

      - name: Install dependencies
        run: npm install

      - name: Run tests
        run: npm test

      - name: Start application
        run: npm start

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