Pattern Library

Reusable code patterns extracted from real projects.

Swift Patterns

Core Architecture

• Observable State - @Observable and @Published patterns
• Navigation Patterns - NavigationStack approaches
• Persistence Patterns - CoreData and UserDefaults
• MVVM with @MainActor ObservableObject - Main actor view model pattern
• MVVM with @MainActor ViewModels - View model architecture
• NavigationStack Route Enum - Enum-based navigation routing
• FullScreenCover Modal Navigation - Modal presentation
• Environment Injection for Services - SwiftUI environment DI
• EnvironmentKey for Layout Metrics - Custom environment keys
• Lazy-Loaded Service Instances - Per-viewmodel service loading
• Protocol-Based Service Abstraction - Service protocol pattern
• Protocol-Based PredictionContent Providers - ML prediction protocols

State & Data

• AppStorage with Enum RawValue Bridge - Enum-backed AppStorage
• CustomTemplateStorage with Observable - Observable storage
• UserPreferences Singleton with AppStorage - Preferences persistence
• Singleton Streak Tracking - Streak tracking manager
• History with Deduplication and Limit - Bounded history
• Enum-Based Content Collections - Static content via enums
• StorySegment Enum - Text/blank segment modeling
• Word Pool Combinatorial Generation - Word combination generator

UI & Theming

• AudioService Singleton - Audio playback service singleton
• AppTheme ThemeManager - Theme management
• ThemeManager EnvironmentObject Injection - Theme via environment
• Semantic Color Aliases - Theme-prefixed color naming
• Color(hex:) Extension - Hex color initialization
• AloysiusTheme Enum with Static Colors - Static color definitions
• AmbientBackground - Ambient background view
• MesmerizingButtonStyle - Custom button styling
• MesmerizingCard - Card component
• MesmerizingTextField - Custom text field
• PressableButtonStyle - Press-responsive button
• ScaleButtonStyle - Scale animation button
• ParticleEmitterView via UIViewRepresentable - UIKit particle bridge
• View ID Modifier for Scene Transitions - Scene transition control
• AnimationPresets Extension - Reusable animation presets
• HapticService with Named Patterns - Haptic feedback service

Audio & System

• SystemSoundID Constants Enum - System sound constants
• Achievement System with Unlock Conditions - Gamification
• as const Object Union Type - Const union pattern
• Silent Error Fallbacks with Nil Coalescing - Graceful error handling

TypeScript Patterns

State & Architecture

• Factory + DI - Factory functions with dependency injection
• Context + Reducer - React state management
• Conversation State Machine - Chat/conversation state management
• TContext Generic - Generic context typing
• Board Management - Board data management
• Immutable Progress Tracker - Immutable state tracking
• Fire-and-Forget Persistence - Async persistence
• Recursive Tree Manipulation - Tree data structure ops
• Dashboard Aggregation - Multi-source dashboard data
• Direct Store Integration Testing - Integration testing stores directly

Audio & Media

• Web Audio - Web Audio API patterns
• SoundGenerator with Presets - Audio generation with presets
• ADSR Synthesis - Attack-decay-sustain-release audio
• Audio Context Autoplay Handling - Browser autoplay workarounds
• Audio Stream Processing - Real-time audio streams
• RecordingService Singleton - Audio recording service

React Hooks

• Vitest Setup with react-ga4 Mocking - Test setup for analytics SDK mocking (source: djg)
• useAudio Hook - React hook for audio
• useKeyboard Hook - React hook for keyboard events
• useCallback for Move Handler - Memoized move handling
• useLongPress Hook - Long press detection
• usePeer Hook - WebRTC peer connection hook

Data & Conversion

• Bidirectional Conversion Pattern - Two-way data conversion pattern
• Graph Health Reporting - Graph health metrics and reporting
• Mode-Based UI Switching - UI mode toggling pattern

Networking & Security

• fetchWithRetry Utility - Retry logic for fetch
• CryptoBackend Interface - Crypto abstraction
• KeyStorage Interface - Key storage abstraction
• WebSocket Broadcast - Cross-device synchronization
• MIME Fallback Chain - Content type fallbacks
• MIME Type Fallback - MIME type resolution

Code Organization

• Stack-Based Scope Tracking - Stack-based variable scope management
• Multi-Pane Productivity Workflow - Terminal pane layout for parallel development tasks
• tmux Session Launcher - Reproducible tmux session configuration
• TypeScript Project References - Vite standard for faster type checking (source: djg)
• CSS Co-location - Keeping styles with components
• ESM Module Separation - Module organization patterns
• Fetch Scripts - Data fetching patterns
• LocalStorage Validation - Storage with validation
• Minimal Interface Types - Lean type definitions
• PascalCase Components, camelCase Services - Naming conventions
• Path Alias src - Import path aliasing
• ReactFC with Explicit Props Types - Component typing
• SliderControl Component - Slider UI component

AI & NLP

• Proposer-Solver-Evaluator - Self-evolving knowledge building loop
• Global Type Augmentation - Extending Window, Document, and module types
• Multi-Stage NL-to-Code Pipeline - Natural language to code generation
• Safe Reflection - Runtime type introspection with safety
• User Persona Simulation - Simulating user behaviors for testing
• Weighted Rule Matching - Priority-based rule evaluation
• Pattern Matcher - Regex with capture groups
• REPL Interface - Interactive command interfaces
• Topic Memory - Context retention patterns
• Eliza Pattern Matching Engine - Classic AI pattern matching
• Eliza Rule Matching - Rule-based response generation
• Response Variety Cycling - Varied response selection

Python Patterns

• Release Readiness Workflow - Pre-release validation workflow
• Environment-Aware Scripts - Scripts that adapt to local vs CI
• Threshold-Based Alerting - 50%/80% warning/critical thresholds
• Contacts Array Preservation - Maintaining array integrity during transforms
• Dry Run Mode - Preview changes before applying
• External ID Deduplication - Dedup via external identifiers
• Headless Rendering with Data Injection - Server-side rendering with dynamic data
• Hunk-Based Diff Workflow - Granular diff processing
• Manual-First Automation Discovery - Manual process before automating
• Natural Language Structure Parsing - Extracting structure from free text
• Polished Mode - Draft vs production output separation
• Security Gate Before Deploy - Pre-deployment security checks
• Single-Block ALP Pseudocode - Atomic pseudocode block format
• Thin Command Wrappers - Rich workflow delegation
• Variables API for Data-Driven Rendering - Dynamic rendering via variable APIs
• Workflow Graph Navigation - Graph-based workflow traversal
• YAML for Structured Data - YAML as structured data format
• FOUC Prevention for Dynamic Theme Properties - Prevent flash of unstyled content during theme load
• Git Branch as Coordination Primitive - Using branch creation as an atomic coordination lock

General Patterns

Architecture & APIs

• BDD-to-Code Pipeline - Gherkin to Robot Framework to code generation
• Centralized Utility API Architecture - Shared org-wide API services
• Data Deduplication Patterns - Dedup strategies and algorithms
• Data Deduplication Architecture - Dedup system design
• Neural Gateway Architecture - Model-agnostic AI inference routing
• Software Dependency Management - Supply chain and dependency patterns
• Graph Builder Helpers - Graph construction utility functions
• Graph Diagnostics - Graph health and diagnostic tooling
• Immutable Graph Editing Helpers - Immutable graph edit operations
• AppwriteService Abstraction - Backend service abstraction
• Centralized Constants File - Constants organization
• Dynamic Source Registry - Pluggable source registration
• EncryptedPayload Type - Encrypted data type definition
• Integration Interface - Connect/GetProjects/CreateTask contract
• IntegrationService Facade - Facade pattern for integrations
• Module Export Services - Functional service exports
• Optional Interface Methods - Variant behavior via optional methods
• Source Adapter ABC - Abstract base class for data adapters
• Unified Directed Graph - Graph data structure

Infrastructure & DevOps

• CI Pipeline - CI/CD pipeline configuration
• CI QA Gate with Representative Graphs - QA gates using graph coverage
• QA Gate Helper - Helper utilities for QA gates
• Reference Repos as Read-Only Archives - Keep upstream URLs documented (source: aloysius-references)
• x64 Platform Awareness - Cross-architecture compatibility
• Circuit Breaker - Fault tolerance for external calls
• Circuit Breaker 3-States - Open/half-open/closed states
• Circuit Breaker Status - Status monitoring for circuit breakers
• Credential Permission Verification - Validating access credentials
• Environment Variable Hygiene - Clean env var management
• Git for Change Tracking - Using git as an audit trail
• Mirror-Based Backup - Mirrored backup strategy
• Pre-commit Format Enforcement - Auto-format on commit
• READMEs in Empty Directories - Preserving directory structure in git
• SecretStr for Credentials - Pydantic secret string handling
• Submodule References - Git submodule organization
• Token Bucket Rate Limiting - Rate limiter implementation
• Token Bucket Rate Limiter - Rate limiter variant
• TruffleHog Exclude-Paths - Exclude staging/research dirs from secret scanning
• TruffleHog Self-Hosted Runner - Install without sudo
• Sequential Dependabot Merge with Rebase Cycle - Safe merge ordering for batch dependency updates
• Docker Template Field Validation - Docker config validation
• Hardware Capacity Documentation - Documenting hardware specs
• Infrastructure Separation - Isolating infra concerns
• Infrastructure Sync Discipline - Keeping infra in sync
• Monorepo Folder Cleanup - Monorepo maintenance
• Sea Captain Port Management - Port registry management
• SSH Fleet Management - Managing SSH across hosts
• Terminal Workflow Optimization - Efficient terminal usage
• Homelab File Management Principles - Home server file org

Security

• 3-Scanner Security Architecture - Multi-scanner security pipeline
• Code Supply Chain Risk - Dependency supply chain risks
• Cryptographic Key Exchange - Key exchange protocols
• Path Traversal Protection - Preventing directory traversal
• Pre-commit Secret Scanning - Scanning for secrets before commit
• Zero Trust External Access - Zero trust security model
• Peer-to-Peer Messaging - P2P communication

Knowledge Vault Patterns

• Cross-Cutting Theme Clusters - Organizing content by themes
• Frontmatter Draft Handling - Managing draft states in frontmatter
• Minimum 2 Wikilinks Per Doc - Connectivity requirement
• Orphan Page Detection - Finding unlinked pages
• Research Integration Pipeline - Staging to vault workflow
• Template File Exclusion - Excluding templates from processing
• Standard Link Parse - Link format parsing
• Domain READMEs with YAML Examples - Structured domain docs
• evaluation.md as Standard POC Deliverable - POC evaluation format
• GAS manifest.json for Critical File Tracking - File manifest tracking
• GAS Planning - Planning methodology patterns
• Graduation Criteria - Promotion criteria for projects
• POC Directory Structure - Proof of concept project layout
• protocol.md as Experimental Process Doc - Process documentation format
• Reference Material in Library - Library organization
• Stub-First Shared Resources - Stub-first development approach
• verification.md Per Phase - Phase verification documents

Data & Validation

• IndexedDB Migration Protocol - IndexedDB schema migration strategy
• Metadata Schema Validation - Runtime metadata schema validation
• createTables() Must Mirror Migrations - DDL must match migration columns (source: haven)
• localStorage Mock in Test Environment - Browser API mocking for Vitest/jsdom (source: djg)
• Category-to-Type Mapping - Mapping categories to types
• Form Component Pattern - Reusable form components
• LocalStorage Persistence - Browser storage persistence
• LocalStorage Persistence with Zod Validation - Validated browser storage
• Perceptual Hash Similarity - Image similarity via perceptual hashing
• Slot Subtraction Algorithm - Availability slot calculation
• Source Adapter Interface - Pluggable data source adapters
• from_dict Serialization - Dictionary serialization pattern
• Zod Schema Validation - Runtime schema validation
• Segment-Based Template Parsing - Template segment extraction
• Session Serialization - Session state persistence
• Tab Persistence via LocalStorage - Tab state persistence
• Template Interpolation with Caching - Cached template rendering
• Template Interpolation Caching - Template interpolation with caching variant

Agentic Patterns

• Agent Scratchpad Workspace - Isolated, agent-owned workspace with three-part structure
• AI Agent Execution Constraints - Loop budgets, spec-first, context boundaries
• Boundary Guard Hooks - Pre-execution file access enforcement
• Context Refresh Session State - Three-mode session state management
• Human-in-the-Loop Approval Gates - Four-category approval taxonomy
• Polyglot Monorepo Architecture - Multi-language monorepo with daemon-client layers
• Multi-Pane Agent Parallelism - Parallel AI agent coordination across terminal panes
• Self-Contained Generated Files - Generated files that work across AI tools without external references

Automation & AI

• AI Context Injection - Injecting context into AI prompts
• Async Session Context Manager - Async context management
• Custom CodeMirror Language - Custom language definition for CodeMirror
• Feature-Based Store Pattern - Feature-scoped state management
• Lazy Directory Loading - On-demand directory traversal
• Monaco Model Registry - Editor model management
• Optional Dependency Import - Graceful optional imports
• Quiz Variation Transforms - Generating quiz variations
• Simulation Service - Service layer for simulations
• SikuliX Visual Automation - Visual UI automation
• Organize Flow - Data capture pipeline
• AI Summarization Pipeline - Multi-stage AI pipeline for summarizing research corpora
• Drift Prediction Visualization - Prediction drift monitoring
• Intelligent Response Generation - Smart response creation
• Monte Carlo Goal Forecasting - Probabilistic goal modeling
• NarrativeEngine Wrapper - Narrative engine abstraction
• Persona System with Rule Precedence - Rule-based persona management
• QuizEngine State Machine - Quiz state management
• Synthetic Data Generation - Generating synthetic datasets
• Procedural Generation Workflows - Procedural content creation

Desktop Automation

• AutoKey Linux Automation - Linux keyboard automation
• GIMP Headless Automation - Headless image processing
• Hammerspoon macOS Automation - macOS window/keyboard automation
• PyAutoGUI Cross-Platform Automation - Cross-platform GUI automation

UI & Components

• GA Event Tracking via Functional Component - Analytics separated from UI (source: djg)
• Tailwind-First Component Styling - Utility-class-only styling convention (source: djg)
• CSS Custom Properties + @theme inline - Runtime theming via CSS custom properties
• Three-Layer Accessibility Enforcement - Audit, automation, and CI-based a11y enforcement
• WCAG Contrast Validation Engine - Automated WCAG contrast ratio checking
• AloysiusTheme Enum with Static Colors - Theme color definitions
• Color(init:hex) Extension - Hex color initialization
• Compliance Verification UI - Compliance check interface
• ErrorBoundary Component - Error boundary pattern
• ErrorBoundary Wrapper Component - Error boundary HOC
• ErrorToast Component - Error notification toast
• MainTabView with AppMode Enum - Tab-based navigation
• Single App Component with useState - Simple app state

React Hooks & State

• Context useReducer Action Types - Typed reducer actions
• Custom Hook useInbox - Inbox context wrapper
• useConnectionStatus Hook - Connection monitoring
• useMemo for Board Layout Parsing - Memoized layout
• useNewMessageNotification Hook - Message notifications
• useRoom Hook - Room context management
• Zustand Persist for Client State - Persistent client state
• Zustand Slice Composition - Modular Zustand store slices
• Write-through Dexie Sync Middleware - Dexie IndexedDB write-through sync

Game & Domain Patterns

• DiceCollection as ObservableObject - Observable dice collection
• DiceType CaseIterable Enum - Dice type enumeration
• Static Factory Method on DiceRoll - Factory method pattern

Process & Methodology

• Consumer Integration Smoke Test - Integration smoke test pattern
• Property-Based Tests - Property-based testing methodology
• Scale Testing - Performance and scale testing patterns
• Telemetry Hooks - Observability via telemetry hook points
• Temporal Middleware Wrapper - Async middleware wrapper pattern
• Atomic File Write - Safe file writing
• Exported Pure Helpers for Testability - Testable pure functions
• handleEventName for Event Handlers - Event handler naming convention
• Idempotent Auto-Creation - Safe repeated creation
• Immutable Effect Processing - Side-effect-free processing
• Market Analysis Before POC - Pre-POC market research
• Phase-Based Incremental Delivery - Phased delivery strategy
• Project with Embedded Tasks - Task embedding in projects
• Safe-First Merge Ordering - Merge conflict prevention
• Snooze) - Reversible user actions

About This Section

Each pattern includes:

• Problem - What challenge it solves
• Solution - The pattern implementation
• Usage - Code examples
• Trade-offs - When to use (and when not to)
• Source - Which project it came from