NodeJS Application Overview

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.

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.

Why Choose Node.js?

High performance with non-blocking I/O
Vast ecosystem via npm
Single language for client and server

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

Compatibility Warning

Always verify that your CI/CD environment (like GitHub Actions) uses the same Node.js version as your local setup to avoid inconsistencies.

Sample Project Structure

Below is a minimal Node.js project that returns “Hello World” from a /hello endpoint.

File	Purpose
package.json	Metadata (name, version), dependencies, and script definitions
index.js	Main application file (defines server and routes)
test.js	Simple test suite to verify the logic in `index.js`

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.

Running Your Tests

Run the test suite defined in test.js:

npm test

Expected output:

> [email protected] test
> node test.js

Testing is successful

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!

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

Links and References

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