Web Component Starter Template

A comprehensive, production-ready starter template for creating Web Components. This template is based on the architecture and best practices from my web components work, incorporating Google's Custom Element Best Practices.

✨ Features

• Modern Tooling: Vitest, ESLint, Prettier, Happy DOM
• Best Practices: Shadow DOM, Custom Elements v1, proper encapsulation, following Google's recommendations
• Multiple Import Options: Auto-define, manual definition, or both
• Testing: Comprehensive test setup with coverage reporting
• CI/CD: GitHub Actions workflows included
• Developer Experience: Demo page, interactive setup, extensive documentation
• Publishing Ready: npm package configuration and automated publishing workflow

🚀 Quick Start

Use This Template

1. Click "Use this template" on GitHub, or:

git clone https://github.com/aarongustafson/web-component-starter.git my-component
cd my-component

2. Run the interactive setup:

npm install
npm run setup

The setup wizard will:

• Ask for your component name (e.g., my-awesome-component)
• Ask for a description
• Rename all files automatically
• Replace all placeholders in code and configuration
• Generate your component's README from template
• Clean up template setup files (SETUP.md, README.tpl, scripts/)
• Install dependencies
• Initialize git repository

Manual Setup

If you prefer manual setup, see SETUP.md for detailed instructions.

📁 What's Included

web-component-starter/
├── COMPONENT-NAME.js                    # Component implementation
├── index.js                             # Main entry (class + auto-define)
├── define.js                            # Auto-define only
├── custom-elements.json                 # Custom Elements Manifest
├── package.json                         # Package config with scripts
├── LICENSE                              # MIT License
├── README.md                            # This file (replaced after setup)
├── README.tpl                           # Template for your component's README
├── WEB-COMPONENTS-BEST-PRACTICES.md    # Best practices documentation
├── .gitignore                           # Git ignore
├── .npmignore                           # npm ignore
├── .prettierrc                          # Prettier config
├── .editorconfig                        # Editor config
├── eslint.config.js                     # ESLint config
├── vitest.config.js                     # Vitest config
├── .github/
│   ├── workflows/
│   │   ├── ci.yml                      # Continuous integration
│   │   └── publish.yml                 # Auto-publish to npm
│   └── ISSUE_TEMPLATE/                 # Bug & feature templates
├── scripts/
│   └── setup.js                        # Interactive setup wizard (removed after setup)
├── test/
│   ├── setup.js                        # Test configuration
│   └── COMPONENT-NAME.test.js          # Test suite
├── demo/
│   └── index.html                      # Live demo page
├── SETUP.md                            # Manual setup guide (removed after setup)
└── CONTRIBUTING.md                     # Contribution guidelines

🛠️ Development

Available Scripts

npm run setup          # Interactive setup wizard
npm test               # Run tests in watch mode
npm run test:run       # Run tests once
npm run test:ui        # Open Vitest UI
npm run test:coverage  # Generate coverage report
npm run lint           # Lint with ESLint + Prettier
npm run format         # Auto-fix linting issues

Component Architecture

This template provides flexible import options:

Option 1: Manual registration

import { ComponentNameElement } from '@yourscope/component-name';

customElements.define('my-custom-name', ComponentNameElement);

Option 2: Guarded auto-define (browser environments only)

import '@yourscope/component-name/define.js';
// Registers the element when customElements is available

Prefer to control when registration happens? Call the helper directly:

import { defineComponentName } from '@yourscope/component-name/define.js';

defineComponentName();

🧪 Testing

Includes:

• Vitest: Fast, modern test runner
• Happy DOM: Lightweight browser environment
• Testing Library: DOM testing utilities
• Coverage: V8 coverage reporting
• UI: Interactive test debugging

Example:

import { describe, it, expect } from 'vitest';

describe('MyComponent', () => {
  it('should render', () => {
    const el = document.createElement('my-component');
    expect(el).toBeInstanceOf(HTMLElement);
  });
});

📦 Publishing

Setup Automated Publishing with OIDC (Recommended)

This template is configured to publish to npm using OpenID Connect (OIDC), which is more secure than using long-lived NPM tokens.

Initial Setup:

1. Publish your package to npm manually the first time:

   npm run test:run  # Ensure tests pass
   npm run lint      # Ensure code is clean
   npm publish       # First publish must be manual

2. Configure OIDC on npm:

   • Visit your package's access page: https://www.npmjs.com/package/@yourscope/your-component-name/access
   • Under "Publishing Access", click "Configure OIDC"
   • Add GitHub Actions as a trusted publisher with these settings:
     • Provider: GitHub
     • Organization/Username: Your GitHub username or organization
     • Repository: Your repository name
     • Workflow: .github/workflows/publish.yml
     • Environment: Leave blank (unless you use GitHub environments)

3. Create a GitHub release to trigger automated publishing:

   • Use npm version to update version and create a tag: npm version patch (or minor/major)
   • Push with tags: git push --follow-tags
   • Or create a release through GitHub's UI

The GitHub Actions workflow (.github/workflows/publish.yml) will automatically publish to npm when you create a new version tag.

Manual Publishing

If you prefer to publish manually without automation:

npm run test:run  # Ensure tests pass
npm run lint      # Ensure code is clean
npm publish       # Publish to npm

🌐 Browser Support

Works in all modern browsers supporting:

• Custom Elements v1
• Shadow DOM v1
• ES Modules

For legacy browsers, use polyfills.

📚 Documentation

• WEB-COMPONENTS-BEST-PRACTICES.md - Explanation of best practices used in this template
• SETUP.md - Detailed setup instructions (removed after setup)
• CONTRIBUTING.md - Contribution guidelines
• LICENSE - MIT License

🎯 Use Cases

Perfect for:

• Reusable UI components
• Design system elements
• Form controls and widgets
• Interactive content blocks
• Accessibility-enhanced components

🙏 Credits

Based on best practices from:

• Google's Custom Element Best Practices
• form-obfuscator by Aaron Gustafson
• Open Web Components

📄 License

MIT - See LICENSE

🤝 Contributing

Contributions welcome! See CONTRIBUTING.md

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Ready to build your web component? Run npm run setup to get started! 🚀