# javascript-pro

> Claude/Codex skill by [@jeffallan](https://omgskills.com/library/jeffallan/index.md) · 12k stars · Updated 2026-10-30

Writes, debugs, and refactors JavaScript code using modern ES2023+ features, async/await patterns, ESM module systems, and Node.js APIs. Use when building vanilla JavaScript applications, implementing Promise-based async flows, optimising browser or Node.js performance, working with Web Workers or Fetch API, or reviewing .js/.mjs/.cjs files for correctness and best practices.

Tags: ai-agents, claude, claude-code, claude-marketplace, claude-skills

## Install

```sh
git clone https://github.com/Jeffallan/claude-skills /tmp/claude-skills && ln -s /tmp/claude-skills/skills/javascript-pro ~/.claude/skills/javascript-pro
```

## From README

JavaScript Pro When to Use This Skill Building vanilla JavaScript applications Implementing async/await patterns and Promise handling Working with modern module systems (ESM/CJS) Optimizing browser performance and memory Developing Node.js backend services Implementing Web Workers, Service Workers, or browser APIs Core Workflow Analyze requirements — Review package.json, module system, Node version, browser targets; confirm .js/.mjs/.cjs conventions Design architecture — Plan modules, async flows, and error handling strategies Implement — Write ES2023+ code with proper patterns and optimisations Validate — Run linter (eslint --fix); if linter fails, fix all reported issues and re-run before proceeding. Check for memory leaks with DevTools or --inspect, verify bundle size; if leaks are found, resolve them before continuing Test — Write comprehensive tests with Jest achieving 85%+ coverage; if coverage falls short, add missing cases and re-run.

## Links

- HTML page: https://omgskills.com/library/jeffallan/claude-skills/javascript-pro/
- GitHub: https://github.com/Jeffallan/claude-skills
- Author: [@jeffallan](https://omgskills.com/library/jeffallan/index.md)

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