JavaScript Developer Skill Skill

Entry point: /faion-net — invoke this skill for automatic routing to the appropriate domain.

JavaScript Developer Skill

JavaScript and TypeScript development covering React, Node.js, Next.js, and modern JS ecosystem.

Purpose

Handles all JavaScript/TypeScript development including React frontends, Node.js backends, Next.js full-stack apps, and modern JS tooling.

Context Discovery

Auto-Investigation

Detect JS/TS stack from project files:

| Signal | How to Check | What It Tells Us | |--------|--------------|------------------| | package.json | Read("package.json") | Dependencies, scripts, type | | React | Grep("react", "package.json") | React framework used | | Next.js | Grep("next", "package.json") | Next.js framework | | Express | Grep("express", "package.json") | Express backend | | Fastify | Grep("fastify", "package.json") | Fastify backend | | TypeScript | Glob("**/tsconfig.json") | TypeScript enabled | | Bun | Glob("**/bun.lockb") | Bun runtime | | ESLint config | Glob("**/.eslintrc*") | Linting setup | | Jest/Vitest | Grep("jest\|vitest", "package.json") | Test framework |

Read existing patterns:

Check src/ structure for architecture
Read existing components for patterns
Check tsconfig.json for strictness level

Discovery Questions

Q1: Project Type

question: "What type of JS/TS project is this?"
header: "Type"
multiSelect: false
options:
  - label: "React frontend (SPA)"
    description: "Client-side React application"
  - label: "Next.js full-stack"
    description: "Server components, API routes, SSR"
  - label: "Node.js backend"
    description: "Express, Fastify, or plain Node"
  - label: "Library/package"
    description: "Reusable npm package"

Routing:

"React" → react-*, component architecture
"Next.js" → nextjs-app-router, server components
"Node.js" → nodejs-express or nodejs-fastify
"Library" → TypeScript strict, build config

Q2: TypeScript Strictness

question: "What TypeScript strictness level?"
header: "TypeScript"
multiSelect: false
options:
  - label: "Strict mode (recommended)"
    description: "Full type safety, no any"
  - label: "Standard"
    description: "Basic type checking"
  - label: "JavaScript only"
    description: "No TypeScript"
  - label: "Match existing config"
    description: "Follow tsconfig.json"

Q3: State Management (if React)

question: "How do you manage state?"
header: "State"
multiSelect: false
options:
  - label: "React hooks (useState, useContext)"
    description: "Built-in React state"
  - label: "Zustand"
    description: "Lightweight global state"
  - label: "Redux/RTK"
    description: "Full Redux toolkit"
  - label: "Server state (React Query/SWR)"
    description: "Remote data fetching"
  - label: "Not sure / recommend"
    description: "I'll suggest based on needs"

When to Use

React applications (hooks, components, state)
Node.js backends (Express, Fastify)
Next.js full-stack applications
TypeScript strict mode and patterns
Modern JavaScript (ES2024+)
Bun runtime

Methodologies

| Category | Methodology | File | |----------|-------------|------| | React | | Component architecture | React component patterns, composition | react-component-architecture.md | | React hooks | useState, useEffect, custom hooks | react-hooks.md | | React patterns | Modern React patterns, best practices | react-patterns.md | | React decomposition | Breaking down React apps | decomposition-react.md | | Next.js | | Next.js App Router | App router, server components, routing | nextjs-app-router.md | | Node.js | | Node.js Express | Express.js patterns, middleware | nodejs-express.md | | Node.js Fastify | Fastify framework, plugins, hooks | nodejs-fastify.md | | Node.js patterns | Async patterns, error handling | nodejs-patterns.md | | Node.js service layer | Service layer architecture | nodejs-service-layer-architecture.md | | Node.js service implementation | Service layer implementation | nodejs-service-layer-implementation.md | | TypeScript | | TypeScript patterns | TS best practices, generics | typescript-patterns.md | | TypeScript strict mode | Strict configuration, type safety | typescript-strict-mode.md | | TypeScript React 2026 | TS 5.x + React 19 + Next.js 15 | typescript-react-2026.md | | JavaScript | | JavaScript basics | ES6+, async/await, modules | javascript.md | | JavaScript modern | ES2024+ features, modern patterns | javascript-modern.md | | JavaScript testing | Jest, Vitest patterns | javascript-testing.md | | Runtime | | Bun runtime | Bun.js patterns, performance | bun-runtime.md | | Bun simple | Quick Bun reference | bun-runtime-simple.md |

Tools

Frameworks: React 19, Next.js 15, Express, Fastify
Runtime: Node.js 20+, Bun 1.x
Testing: Jest, Vitest, React Testing Library
Bundlers: Vite, Turbopack, webpack
Package managers: pnpm, npm, yarn, bun

Related Sub-Skills

| Sub-skill | Relationship | |-----------|--------------| | faion-frontend-developer | UI components, styling | | faion-api-developer | API design and integration | | faion-testing-developer | Testing strategies | | faion-devtools-developer | Build tools, monorepos |

Integration

Invoked by parent skill faion-software-developer when working with JavaScript/TypeScript code.

faion-javascript-developer v1.0 | 18 methodologies

Agent Skills: JavaScript Developer Skill

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Skill Files