TypeScript Modular Refactor with Legacy Preservation

[Copilot]

Implements a complete TypeScript modular refactor of the portfolio application while preserving the original monolithic app.js as an alpha legacy build.

Overview

This refactor transforms the single-file JavaScript application into a modern, maintainable TypeScript codebase with 13 focused modules, while ensuring the original functionality remains accessible as app.legacy.js.

Key Changes

🏗️ Modular Architecture

• 13 TypeScript modules organized by responsibility:
  • src/components/ - UI component handlers (certifications, cards, panel)
  • src/three/ - 3D graphics (nebula, starfield, galaxy, halo, scene management)
  • src/canvas/ - 2D effects (layout, flow field, grid distortion)
  • src/controls/ - User input and interaction handling
  • src/main.ts - Application entry point

🔒 Type Safety

• Strict TypeScript configuration with full type coverage
• Interface definitions for all major data structures
• Compile-time error prevention for Three.js API usage

⚡ Modern Development Workflow

• Vite development server with hot module replacement
• TypeScript compilation with strict settings
• Vitest test framework setup (jsdom environment)
• Build scripts: npm run dev, npm run build, npm run test

🎨 Preserved Functionality

All original features maintained with identical behavior:

• Interactive 3D galaxy with adaptive quality settings
• Vertex/fragment shaders preserved verbatim
• Flow field visualization and grid distortion effects
• Responsive canvas resizing and mobile optimizations
• UI component interactions (expandable cards, certification toggle)

📚 Legacy Support

• Original app.js renamed to app.legacy.js with documentation header
• Clear instructions in README for switching back to legacy version
• Both versions tested and verified to work identically

Technical Implementation

The refactor maintains the exact same visual output and performance characteristics while providing:

1. Clean separation of concerns - Each module has a single responsibility
2. Type safety - Prevents runtime errors through compile-time checking
3. Better maintainability - Focused modules are easier to understand and modify
4. Modern tooling - Development experience improvements with Vite and TypeScript

Migration Path

Users can easily switch between versions:

New TypeScript version (default):

<script type="module" src="/src/main.ts"></script>

Legacy version:

<script type="module" src="app.legacy.js"></script>

The 3D galaxy visualization continues to work perfectly with all interactive effects, quality adaptation, and responsive design intact.

This pull request was created as a result of the following prompt from Copilot chat.

Implement the TypeScript modular refactor while preserving the original monolithic app.js as an alpha legacy file.

User preference just confirmed: Keep legacy script as an alpha release – rename existing app.js to app.legacy.js (and reference it in README as an "Alpha Legacy Build"). Do NOT load it by default in index.html; only document how to switch back.

Tasks:

1. Rename root app.js -> app.legacy.js (no code changes inside except a header comment noting legacy/alpha).
2. Add TypeScript project structure under /src as previously outlined:
   src/components/certifications/CertificationsToggle.ts
   src/components/cards/CardExpand.ts
   src/components/panel/PanelClouds.ts
   src/components/quality/Settings.ts
   src/three/ThreeSetup.ts
   src/three/Nebula.ts
   src/three/Starfield.ts
   src/three/Galaxy.ts
   src/three/Halo.ts
   src/three/SceneBuilder.ts
   src/canvas/Layout.ts
   src/canvas/FieldGrid.ts
   src/controls/Controls.ts
   src/main.ts
   src/types/global.d.ts
3. Migrate logic from legacy file into these modules. Preserve shader code verbatim. Fill in previously abbreviated sections (the original snippet had ellipses) carefully or annotate with TODO if the original repo content (truncated in context) must be copied—retrieve full file content if accessible; otherwise isolate incomplete blocks behind TODO comments so build still passes.
4. Introduce package.json with scripts:
   • dev: vite
   • build: tsc && vite build
   • preview: vite preview
   • test: vitest run
     Add dependencies: three ^0.155.0; devDependencies: typescript, vite, vitest, @types/node, jsdom (for DOM tests), @types/jsdom.
5. Add tsconfig.json (strict) & vitest.config.ts (jsdom environment).
6. Update (or create) README.md: new Architecture section, Dev commands, Legacy alpha usage (how to swap to legacy by adding a script tag referencing app.legacy.js and removing module entry).
7. Modify index.html: include <script type="module" src="/src/main.ts"></script>; remove old <script src="app.js"> if present. Keep any existing HTML content unchanged otherwise.
8. Implement quality dropdown rebuild: when changed, call a rebuild function exported from SceneBuilder (e.g., rebuildScene(newQuality)). Provide a setter in Settings.ts to update quality state and trigger rebuild.
9. Provide main animation loop in main.ts (lift from legacy). Ensure reduced motion checks & requestAnimationFrame logic preserved.
10. Provide tests:
    tests/components/CertificationsToggle.test.ts (toggle presence & aria-expanded)
    tests/components/quality/Settings.test.ts (simulate different environment inputs; mock navigator/deviceMemory & window.devicePixelRatio where needed).
11. ESLint not required for this iteration; optional TODO in README.
12. Ensure no console errors at runtime (guard null DOM references; feature-detect ResizeObserver etc.).
13. Add .gitignore for node_modules, dist, .DS_Store, npm-debug.log*, vite cache.
14. Add a simple type for ObjectDescriptor used in objects array.
15. Expose star count update in SceneBuilder (accept starCountEl: HTMLElement | null).
16. Leave legacy file unreferenced by build, but clearly labeled.

Acceptance:

• Project builds (vite) & TypeScript passes.
• Tests pass.
• Visual & interactive parity with legacy (within reason; if any minor divergence, explain in PR description under a "Parity Notes" subsection).

Update the existing WIP PR (if tooling creates a new PR, mark old one superseded in description).

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