Use when writing JavaScript/TypeScript code, implementing control flow or state management, fixing type errors, adding validation or error handling, optimizing performance (loops, conditionals,...

A practical, jargon-free guide to functional programming - the 80/20 approach that gets results without the academic overhead

Everyday data transformations using functional patterns - arrays, objects, grouping, aggregation, and null-safe access

Practical patterns for composing functions in TypeScript using pipe, flow, and functional design principles

Master functional approaches to side effects including IO types, effect isolation, idempotent operations, and quarantining impure code - essential patterns for reliable TypeScript applications

Clerk authentication for Next.js 16 (App Router only) with proxy.ts setup, migration from middleware.ts, environment configuration, and MCP server integration.

Provides Playwright test patterns for resilient locators, Page Object Models, fixtures, web-first assertions, and network mocking. Must use when writing or modifying Playwright tests (.spec.ts,...

Use when writing, reviewing, or refactoring vitest tests. Load when you see *.test.ts or *.spec.ts files, nested describe blocks, loose assertions (toBeTruthy), over-mocking, slow tests, or async...

TypeScript 타입 정의 및 베스트 프랙티스 스킬. 다음 상황에서 사용: (1) TypeScript 파일(.ts, .tsx) 작성 또는 수정 시, (2) 타입 정의(interface, type) 작업 시, (3) tsconfig.json 설정 또는 컴파일러 옵션 조정 시, (4) 타입 에러 해결 또는 타입 안전성 개선 시, (5) 제네릭,...

React Testing Library 및 Vitest 기반 테스팅 모범 관례. 다음 상황에서 사용: (1) .test.tsx, .test.ts, .spec.tsx, .spec.ts 파일 작업 시, (2) 컴포넌트 테스트 작성 또는 리팩토링 시, (3) 'test', 'testing', 'vitest', 'RTL', 'getByRole',...

Expert in JSON:API serialization patterns using ts-jsonapi or similar libraries.

Set up Trigger.dev in your project. Use when adding Trigger.dev for the first time, creating trigger.config.ts, or initializing the trigger directory.

Configure Trigger.dev projects with trigger.config.ts. Use when setting up build extensions for Prisma, Playwright, FFmpeg, Python, or customizing deployment settings.

Validate Next.js 16 configuration and detect/prevent deprecated patterns. Ensures proxy.ts usage, Turbopack, Cache Components, and App Router best practices. Use before any Next.js work or when...

Modern TypeScript project architecture guide for 2025. Use when creating new TS projects, setting up configurations, or designing project structure. Covers tech stack selection, layered...

Creates JavaScript classes using Bun's Zig bindings generator (.classes.ts). Use when implementing new JS APIs in Zig with JSC integration.

Use when working with Payload projects (payload.config.ts, collections, fields, hooks, access control, Payload API). Use when debugging validation errors, security issues, relationship queries,...

Dead code cleanup and consolidation specialist. Use PROACTIVELY for removing unused code, duplicates, and refactoring. Runs analysis tools (knip, depcheck, ts-prune) to identify dead code and...

Modern JavaScript/TypeScript development with Bun runtime. Covers package management, bundling, testing, and migration from Node.js. Use when working with Bun, optimizing JS/TS development speed,...

Modern JavaScript/TypeScript development with Bun runtime. Covers package management, bundling, testing, and migration from Node.js. Use when working with Bun, optimizing JS/TS development speed,...