Best SKILL.md Skills for JavaScript Developers (2026)

A skill is a set of instructions packaged as a SKILL.md file that an AI agent reads to learn a new workflow. JavaScript-specific skills teach AI coding agents to follow your framework conventions, handle async patterns correctly, use your package manager, and write TypeScript that actually compiles.

Quick Answer: The best skills for JavaScript developers cover TypeScript type generation, React/Vue/Svelte component patterns, Jest/Vitest test generation, ESLint/Prettier enforcement, and Node.js API patterns. All use the SKILL.md format and work across Claude Code, OpenClaw, Codex CLI, Cursor, and Gemini CLI. Browse them at agensi.io/skills.

Why do JavaScript developers need specific skills?

The JavaScript ecosystem has more tooling choices than any other language. React or Vue? Jest or Vitest? npm, pnpm, or yarn? CommonJS or ESM? Tailwind or CSS modules? Each project makes different choices, and generic AI agents default to the most common patterns — which might not be yours.

A JavaScript-specific skill tells the agent which choices your project made. No more correcting import styles, removing semicolons, or switching from var to const after every generation.

What are the best TypeScript skills?

TypeScript skills enforce strict typing conventions. The best ones generate proper type definitions, avoid any, use discriminated unions where appropriate, and handle generic types correctly.

Key features: automatic tsconfig.json detection (strict mode, path aliases), proper type inference instead of over-typing, and interface vs type alias consistency matching your existing codebase.

What are the best React skills?

React-specific skills handle the patterns that generic agents get wrong: proper hook usage (dependency arrays, custom hook extraction), component composition patterns, state management conventions (local state vs context vs external store), and error boundary implementation.

The frontend-design skill on Agensi covers React component generation alongside broader frontend patterns.

What are the best Node.js API skills?

Backend JavaScript skills cover Express/Fastify/Hono patterns, middleware conventions, error handling (async error propagation, error response format), database query patterns, and API response structures.

A good Node.js skill prevents the common agent mistakes: forgetting to await async operations, not handling promise rejections, using blocking I/O, and inconsistent error response formats.

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What are the best testing skills for JavaScript?

JavaScript testing skills detect your framework (Jest, Vitest, Mocha, Playwright, Cypress) and generate tests using the correct API. The best ones handle:

• Component testing with Testing Library (screen queries, user events)
• API testing with supertest or native fetch
• E2E testing with Playwright or Cypress
• Mock patterns (jest.mock, vi.mock, MSW)

For a broader overview, read Best Testing Skills for AI Agents.

How do I build a JavaScript-specific skill?

---
name: js-standards
description: Use when writing JavaScript or TypeScript, generating components, or reviewing JS/TS code.
---

# JavaScript Standards

## Language
- TypeScript strict mode, no `any`
- ESM imports (import/export), never CommonJS
- Prefer const, use let when reassignment is needed

## Framework
- React 18+ with functional components
- Next.js App Router
- Tailwind CSS

## Package manager
- pnpm only (not npm or yarn)

## Testing
- Vitest for unit/integration tests
- Playwright for E2E
- Testing Library for component tests
- No enzyme, no snapshot tests

Install to any agent's skills directory. The same file works across Claude Code, OpenClaw, Codex CLI, and Cursor.

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Browse JavaScript-compatible skills for any AI coding agent on Agensi.