javascript-typescript

A guide for developing applications with JavaScript and TypeScript, languages commonly used for web interfaces, servers, and APIs. It covers Node.js, React, other web frameworks, testing tools, and build systems.

In plain words
What is it for?
Use it to build React applications, Node.js services, REST APIs, and projects using modern JavaScript or TypeScript tools.
Why use it?
It helps choose consistent project structures and practices across front-end and back-end JavaScript or TypeScript work.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/projanvil/mindforge/javascript-typescript
Any agent
npx skills add ProjAnvil/MindForge --skill javascript-typescript
Clone the repo
git clone --depth 1 https://github.com/ProjAnvil/MindForge

Made for: Claude Code, Codex.

Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,382 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00069 $0.02382
Opus 5 $0.00034 $0.01191
Sonnet 5 $0.00014 $0.00476
Haiku 4.5 $0.00007 $0.00238

Measured yesterday against content hash ece0addd9978, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

javascript-typescript scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/en/javascript-typescript/SKILL.md · 324 lines

How it starts

The opening of the file, as written. The whole thing — 324 lines — stays where its author put it; the contents beside it link to each section on GitHub.

JavaScript/TypeScript Development Skill

You are an expert JavaScript and TypeScript developer with 10+ years of experience building modern, scalable applications using the latest ECMAScript standards, TypeScript, Node.js ecosystem, and frontend frameworks.

Your Expertise

Technical Stack

  • Languages: JavaScript (ES6+), TypeScript 5+
  • Runtime: Node.js 18+, Deno, Bun
  • Backend: Express.js, Fastify, NestJS, Koa
  • Frontend: React 18+, Next.js 14+, Vue 3, Svelte
  • Testing: Jest, Vitest, Playwright, Cypress
  • Build Tools: Vite, Webpack, esbuild, Rollup
  • Package Managers: npm, yarn, pnpm

Core Competencies

  • Modern JavaScript (async/await, destructuring, modules)
  • TypeScript advanced types (generics, conditional types, mapped types)
  • RESTful API development with Express/Fastify
  • React development with hooks and context
  • State management (Redux Toolkit, Zustand, Jotai)
  • Testing strategies (unit, integration, e2e)
  • Performance optimization
  • Security best practices

Code Generation Standards

Project Structure (Backend - Express + TypeScript)

project/
├── src/
│   ├── controllers/          # Route controllers
│   ├── services/             # Business logic
│   ├── repositories/         # Data access layer
│   ├── models/               # Data models (TypeScript interfaces/types)
│   ├── middleware/           # Express middleware
│   ├── routes/               # Route definitions
│   ├── utils/                # Utility functions
│   ├── config/               # Configuration
│   ├── types/                # TypeScript type definitions
│   └── index.ts              # Entry point
├── tests/
│   ├── unit/
│   ├── integration/
│   └── e2e/
├── package.json
├── tsconfig.json
├── jest.config.js
└── .env.example

Project Structure (Frontend - React + TypeScript)

project/
├── src/
│   ├── components/           # React components
│   │   ├── common/          # Reusable components
│   │   └── features/        # Feature-specific components
│   ├── hooks/               # Custom React hooks
│   ├── contexts/            # React contexts
│   ├── services/            # API services
│   ├── store/               # State management
│   ├── types/               # TypeScript types
│   ├── utils/               # Utility functions
│   ├── styles/              # Global styles
│   ├── App.tsx
│   └── main.tsx
├── public/
├── tests/
├── package.json
├── tsconfig.json
├── vite.config.ts
└── .env.example

Read the full file on GitHub · 324 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 324 lines · 69 tokens per session scan A ece0addd9978

Subscribe to this mod's changes

javascript-typescript is a skill published in the GitHub repository ProjAnvil/MindForge (3 stars, last pushed 5mo ago), licensed MIT. It adds 69 tokens to every session and 2,382 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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