Ever tried deploying a Single Page Application (SPA) with a modular JavaScript structure to GitHub Pages, only to encounter unexpected errors? This article details a common hurdle faced by many developers and its simple, yet crucial, solution, offering practical insights for navigating your first modular deployments.

Understanding Modular vs. Simple Web Apps

Let’s first clarify the distinction between a simple web application and a modular SPA:

• Simple Web Application: Typically consists of a few core files:
  /simple web application
|---- index.html
|---- main.js
|---- style.css
• Modular (Single Page Application): Features a more organized structure with multiple JavaScript modules and dedicated folders:
  /Modular (Single Page Application)
├── index.html
├── /js/
│ ├── app.js
│ ├── router.js
│ └── views/
│ ├── HomeView.js
│ ├── CompletedView.js
│ └── StatsView.js
└── /css/
└── style.css
  This modular approach helps manage complexity but introduces unique deployment considerations.

The Deployment Challenge

When I completed my first modular SPA, a “Contact Manager,” I was eager to showcase it on GitHub Pages. However, directly pushing a project with a complex folder structure via GitHub’s browser-based drag-and-drop isn’t straightforward. It typically only accepts individual files, not entire directories.

My initial workaround was to create a flattened copy of the project. I moved all files to the root level and adjusted import paths accordingly – for example, changing '/src/js/router.js' to '/router.js'. After testing this flattened version locally, where it worked perfectly, I pushed it to a new GitHub repository and deployed it. To my dismay, the live site was broken, showing errors instead of my working application.

Consulting for Insights: Why GitHub Pages Behaves Differently

Confused by the discrepancy between local and deployed behavior, I turned to an AI assistant for an explanation. It provided crucial insights into how modular JavaScript projects interact with static hosting services like GitHub Pages:

“When you create a modular JavaScript project (like an SPA with ES modules), your files are split across multiple JS modules. The browser needs to load each imported file separately, respecting the module system. However, GitHub Pages (and normal static hosting) just serves plain files — it doesn’t ‘build’ or bundle your project like tools such as npm/Vite do. So if your folder structure or import paths aren’t correct (especially case sensitivity or relative paths), or if your imports use local paths, it can break after deployment.”

The assistant highlighted several common reasons for deployment failure, including:
1. Missing type="module": Essential for ES module imports.
2. Wrong import paths: Case sensitivity (./Utils.js ≠ ./utils.js) can cause issues.
3. Root-relative imports fail: This was the critical point. Importing with /src/... (root-relative paths) often breaks on static hosts.
4. Incorrect file uploads: Ensuring the exact folder structure is maintained during upload.
5. index.html not at the root: GitHub Pages serves from the repository root by default.

The Simple Yet Profound Solution

While my local flattened version worked and I’d avoided most of the common pitfalls, the core issue remained: how GitHub Pages interpreted my import paths. The AI assistant’s final suggestion proved to be the game-changer: update all import paths to be current-directory-relative by prefixing them with ./.

This meant changing imports like '/app.js' to './app.js' and '/style.css' to './style.css'. Essentially, adding a . before every import path in the project.

Upon applying this small change and redeploying, my modular SPA sprang to life on GitHub Pages!

Key Lessons Learned

This experience taught me several invaluable lessons about deploying modular JavaScript projects:

• Pathing is Paramount: The way you reference files (import paths) is critical. While root-relative paths (/) might work on a local development server, static hosting environments like GitHub Pages often require current-directory-relative paths (./).
• Local Server vs. Deployment Environment: Don’t assume a perfect replication. What works locally might not work once deployed due to differences in how file paths are resolved.
• Embrace Errors: Every error, however frustrating, is an opportunity to learn a new concept or deepen your understanding. This small issue revealed a fundamental aspect of web deployment.

I successfully deployed my first modular project, and the journey taught me more than just technical fixes; it reinforced the mindset of viewing problems as part of the learning process.

Live Demo: https://github.com/rooqidev/Contact-Manager-SPA-/
Source Code: https://github.com/rooqidev/Contact-Manager-SPA-/