🧩 TS Playground

TypeScript experiments and architecture sketches by risk.
Code featured in my Zenn articles.

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💡 This repository contains small TypeScript experiments,
design pattern trials, and clean architecture prototypes, etc.

Each directory or file is mostly self-contained —
feel free to explore any of them.

Playground means: you can break it, fix it, or rebuild it — that's the point. 🎈

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🚀 Getting Started

Setup

# Clone the repository
git clone https://github.com/risk/ts-playground.git
cd ts-playground

# Install dependencies
npm install

Run Examples

# Run any TypeScript file directly with tsx
npx tsx src/pipeline/pipeline.ts
npx tsx src/recursiveMonad/recursiveMonad.ts
npx tsx src/cleanArchitecture/cleanArchitecture.ts
npx tsx src/keyedPromiseAll/keyedPromiseAllv2.ts
npx tsx src/typeCalc/typeTest.ts
npx tsx src/mappedType/mappedType.ts
npx tsx src/distributiveConditionalType/distributiveConditionalType.ts
npx tsx src/caFramework/sandbox.ts
npx tsx src/gatePrototype/gatePrototype.ts
npx tsx src/gatePrototype/asyncGatePrototype.ts

# Or compile and run
npm run build
node dist/pipeline/pipeline.js

📚 Projects

These descriptions were written by Cursor AI. 🤖

🔗 Type-safe Pipeline

Railway Oriented Programming with full type safety.

• Error recovery mechanisms
• Composable pipeline structure
• Zero runtime overhead

🔄 Recursive Monad

Converting recursion into a chain structure to avoid stack overflow.

• Bidirectional linked list
• Generator-based lazy evaluation
• Applicable to tree/graph traversal

🏗️ Clean Architecture

Sample implementation of Clean Architecture pattern.

• Layer separation (Entity, UseCase, Gateway, Presenter)
• Dependency injection
• Result type pattern

🔢 Type-level Arithmetic

Four arithmetic operations implemented at the type level.

• Addition, subtraction, multiplication, division
• Numbers represented as array lengths
• Pure type-level computation with zero runtime cost

📖 Type System Learning

Educational examples for understanding TypeScript's type system.

• extends and infer keyword usage
• Deconstructing function types with Parameters and ReturnType
• Array pattern matching with conditional types

🍎 Mapped Types with Fruits

Learn Mapped Types through a fun fruit-themed tutorial.

• Step-by-step explanation from Record to Mapped Types
• Understanding as const and type widening
• Transforming types (arrays, functions with arguments)
• Practical pattern: function table with type constraints

🔀 Distributive Conditional Types

Deep dive into how TypeScript distributes union types in conditional types.

• How T extends U distributes over unions
• Preventing distribution with [T] wrapper
• Implementing Extract and Exclude from scratch
• Boolean literal expansion behavior

🏛️ CA Framework Sandbox

Type-level enforcement of Clean Architecture dependency rules.

• Layer dependency validation at compile-time
• InterfacePolicy for declaring allowed consumers
• LayerPolicy for bidirectional dependency checking
• Architectural constraints as TypeScript types

❌ Keyed Promise.all v1 - Failed Attempt

Enhanced Promise.all that returns results by meaningful keys instead of array indices.

• Type inference issues: Function types get reduced to constraints
• Kept as a learning example of TypeScript's limitations

✅ Keyed Promise.all v2

Improved version with perfect type inference using class-based wrapping.

• Builder pattern for fluent API design
• Perfect type inference through KeyedFunc wrapper class
• Result type pattern for type-safe error handling
• handleResult helper for convenient result processing

🚪 Zod Gate Processing

Type-safe data validation and transformation using Zod schemas.

• Input/Output validation with strict schema enforcement
• Curried function design for reusable gate handlers
• Synchronous and asynchronous versions
• Complete type safety with external data isolation
• Unified error handling with custom GateError types

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🪶 License

Licensed under the MIT License.
Free to learn, remix, and build upon.