¶ 1. Overview
This Technology Architecture defines the underlying technology decisions for LUNA Charts. It describes the runtime environment, rendering technology, programming language, distribution model, testing strategy, and release pipeline.
LUNA Charts is designed as a modern, accessibility-first charting library optimized for web environments, focusing on performance, consistency, and WCAG-oriented rendering behavior.
¶ 2. Rendering Technology
¶ SVG-based Rendering Model
LUNA Charts uses SVG (Scalable Vector Graphics) as its primary rendering technology.
¶ Rationale
- Enables element-level accessibility (focusable nodes)
- Supports ARIA attributes per visual element
- Allows keyboard navigation across chart components
- Provides native DOM structure for assistive technologies
- Ensures compatibility with WCAG 2.2 requirements
¶ Exclusion of Canvas
Canvas-based rendering is explicitly excluded because:
- It produces pixel-based output without semantic structure
- Individual chart elements cannot be addressed or focused
- Accessibility must be simulated externally (insufficient for WCAG goals)
- It conflicts with the “Accessibility by Design” principle
¶ 3. Programming Language
¶ TypeScript
LUNA Charts is implemented in TypeScript.
¶ Rationale
- Strong typing for chart-specific data models
- Early error detection at compile time
- Improved developer experience (DX) via IntelliSense
- Explicit API contracts for all chart components
- Supports structured accessibility-related metadata
¶ Architectural Impact
- Each chart type has a dedicated strongly typed data model
- Invalid configurations can be detected before runtime
- Improves reliability of accessibility-related constraints
¶ 4. Framework Integration Strategy
¶ Framework-Neutral Core with Adapter Layer
LUNA Charts is designed as a framework-agnostic system.
¶ Architecture Model
- Core rendering and logic are framework-independent
- Framework-specific adapters provide integration layers
¶ Supported Environments
- React
- Vue
- Angular
- Web Components
¶ Rationale
- Prevents vendor lock-in
- Ensures consistent behavior across frameworks
- Aligns with “Framework Agnosticism” principle (P02)
- Maximizes adoption across ecosystems
¶ 5. Distribution Strategy
¶ Single-Package Consumption Model
LUNA Charts is distributed as a single unified package.
¶ Characteristics
- No plugin system
- No external extensions by consumers
- All functionality is included in the core distribution
¶ Example Usage
npm install luna-charts
<BarChart data={...} />
¶ Rationale
- Simplifies developer experience
- Ensures consistent API behavior
- Maintains strict control over accessibility compliance
- Avoids fragmentation of implementation quality
¶ 6. Testing & Quality Strategy
LUNA Charts follows a multi-layer quality assurance model.
¶ 6.1 Functional Testing
- Unit Tests for core logic
- Ensures correctness of rendering pipeline
¶ 6.2 Accessibility Testing
- Automated accessibility validation tools
- Checks WCAG-related constraints where machine-verifiable
- Ensures ARIA structure correctness
¶ 6.3 Code Quality (Linting)
- Enforces architectural consistency
- Prevents API misuse patterns
- Ensures maintainable code structure
¶ 6.4 Visual Regression Testing
- Ensures SVG rendering stability
- Detects unintended layout or structural changes
- Validates accessibility-relevant DOM consistency
¶ 6.5 Usability Testing
- Manual or moderated usability sessions with representative developers/end users
- Validates real-world developer experience and end-user comprehension of charts
- Required for minor and major releases (new chart types, API changes, significant UX changes)
- Not required for patch releases (bug fixes, internal refactors with no user-facing change)
¶ Release Gate Policy
- Automated testing (unit, accessibility, linting, visual regression) is a blocking condition for every release
- Usability testing is a blocking condition for minor and major releases, but is skipped for patch releases to avoid delaying critical fixes
¶ Release Gate Policy
All test layers are blocking conditions for releases.
¶ 7. Release & Distribution Model
¶ Open Source Release Pipeline
LUNA Charts is developed as an open-source project.
¶ Distribution Flow
¶ Versioning Strategy
Semantic Versioning (SemVer):
- MAJOR: breaking API or chart model changes
- MINOR: new features or chart types
- PATCH: bug fixes and accessibility improvements
¶ 8. Runtime Environment
¶ Modern Browser & Mobile Support
LUNA Charts targets modern web environments.
¶ Constraints
- Modern browsers only (Evergreen browsers)
- Mobile-first compatibility
- No legacy browser support
¶ Rationale
- Enables SVG-first accessibility design
- Reduces polyfill and compatibility overhead
- Improves performance and maintainability
¶ 9. Key Architectural Decisions
- SVG is the only rendering technology (Canvas excluded)
- TypeScript is used for strict typing and API contracts
- Framework-neutral core with adapter layers
- Single-package distribution model
- No plugin or extension system
- Multi-layer testing strategy with release gating
- Open-source distribution via GitHub and npm
- Modern browser and mobile-first runtime strategy
¶ 10. Trade-offs
¶ Advantages
- Strong accessibility guarantees
- Predictable and deterministic rendering
- High developer experience (DX)
- Consistent cross-framework behavior
- Simplified integration model
- High quality assurance via release gates
¶ Limitations
- Limited extensibility for external developers
- Reduced customization flexibility
- Strict architectural constraints
- No plugin ecosystem
- Higher responsibility on core maintainers
¶ 11. Change Log
This document reflects a refined Technology Architecture based on iterative architectural decisions across Phase A (Vision), Phase B (Business Architecture), and Phase C (Application Architecture). Key clarifications introduced in this phase: - SVG confirmed as the only rendering technology due to accessibility requirements - Accessibility is treated as a cross-cutting concern supported by type safety, runtime validation, and internal quality assurance (not a standalone engine) - Framework neutrality enforced through adapter-based architecture - Distribution model defined as a single-package open-source release via npm and GitHub - Testing strategy defined as a multi-layer quality gate system (unit, accessibility, linting, visual regression) - Runtime scope restricted to modern browsers and mobile-first environments for performance and accessibility alignment