🚀 Day 37: GitHub Actions – Matrix Builds with Node.js + Jest

Welcome to Day 10 of your DevOps journey! Today, we’re diving into GitHub Actions to master matrix builds, test a Node.js app across multiple Node versions (18.x, 20.x, 22.x), and troubleshoot compatibility issues. Let’s build a robust CI pipeline with Jest! 🎉

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📌 Goals

By the end of this guide, you’ll know how to:

• 🛠️ Use matrix builds in GitHub Actions to test across multiple environments.

• ✅ Test Node.js code across Node versions 18.x, 20.x, and 22.x.

• 🔍 Identify and troubleshoot compatibility issues.

• ⚙️ Write clean CI pipelines for Node.js + Jest.

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🛠️ Step 1: Project Setup

Let’s create a new project and set up Jest for testing.

1. Create a project folder and initialize a Node.js app:

    mkdir matrix-demo && cd matrix-demo
    npm init -y
   

2. Install Jest as a dev dependency:

    npm install --save-dev jest
   

3. Your package.json should look like this:

{
  "name": "matrix-demo",
  "version": "1.0.0",
  "main": "index.js",
  "scripts": {
    "test": "jest"
  },
  "license": "ISC",
  "devDependencies": {
    "jest": "^30.0.5"
  }
}

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📄 Step 2: Create App and Test Files

app.js

Create a simple function to test:

function add(a, b) {
  return a + b;
}

module.exports = add;

app.test.js

Write a Jest test for the add function:

const add = require('./app');

test('adds 1 + 2 to equal 3', () => {
  expect(add(1, 2)).toBe(3);
});

Test Locally

Run the tests to verify everything works:

npm test

Expected Output:

PASS  ./app.test.js
✓ adds 1 + 2 to equal 3 (1 ms)

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🚀 Step 3: Push Code to GitHub

Push your project to a GitHub repository:

git init
git remote add origin https://github.com/ritesh355/matrix-demo.git
git add .
git commit -m "Initial commit with jest test"
git push -u origin main

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⚙️ Step 4: Add GitHub Actions Workflow

Create a matrix build workflow to test across Node.js versions.

1. Create the file .github/workflows/test.yml:

name: Matrix Test Workflow

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

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [18.x, 20.x, 22.x]

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

      - name: Setup Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}

      - name: Install Dependencies
        run: npm ci

      - name: Run Tests
        run: npm test

2. Commit and push the workflow:

git add .github/workflows/test.yml
git commit -m "Add matrix build workflow"
git push

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✅ Step 5: View the Workflow in GitHub

1. Go to your GitHub repository → Actions tab.

2. You’ll see the Matrix Test Workflow running three parallel jobs:

   • Node 18.x ✅

   • Node 20.x ✅

   • Node 22.x ✅

3. If any job fails, check for compatibility issues (e.g., Jest or syntax problems).

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🔍 Troubleshooting

Common Error

failed to fetch oauth token... 401 Unauthorized

✅ Solution

• This error is typically related to Docker credentials but isn’t applicable here unless you’re pushing images.

• For matrix builds, ensure your GitHub Actions workflow is correct and dependencies are compatible with all Node versions.

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🧠 What You Learned

• ✅ How to test code across multiple Node.js versions using matrix builds.

• ⚙️ Setting up a GitHub Actions pipeline with Jest.

• 🔍 Managing dependency compatibility across environments.

• 🚀 Writing clean, efficient CI pipelines for Node.js projects.

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🔗 Resources

• 📚 GitHub Actions Matrix Strategy

• 🧪 Jest Documentation

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✍️ Author

Ritesh Singh

• 🔗 GitHub: ritesh355

• ✍️ Blog: ritesh-devops.hashnode.dev

• 💼 LinkedIn: Ritesh Singh

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🎉 Congratulations!

You’ve successfully set up a matrix build with GitHub Actions to test your Node.js app across multiple versions! Keep rocking your DevOps journey! 💪

Need help? Drop a comment or question, and I’ll guide you through any issues!