Overview
javascript-pro is an open-source frontend skill for Claude Code and compatible agents, published by Jeffallan. Its author describes it as: “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 as…”. The project has 11k stars on GitHub and is available under the MIT license. Add it to your setup with `/plugin marketplace add Jeffallan/claude-skills`.
What javascript-pro does
- Building vanilla JavaScript applications - Implementing async/await patterns and Promise handling - Working with modern module systems (ESM/CJS) - Optimizing browser performance and memory usage - Developing Node.js backend services - Implementing Web Workers, Service Workers, or browser APIs
What’s inside
The SKILL.md for javascript-pro is organised into these sections:
- When to Use This Skill
- Core Workflow
- Reference Guide
- Constraints
- MUST DO
- MUST NOT DO
- Key Patterns with Examples
- Async/Await Error Handling
- Optional Chaining & Nullish Coalescing
- ESM Module Structure
- Avoid var / Prefer const
- Output Templates
Installation
Add javascript-pro to your agent with:
/plugin marketplace add Jeffallan/claude-skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
License
javascript-pro is published under the MIT license.
Strengths
- Clear MIT license — safe to read and adapt within its terms
- Ships in Jeffallan/claude-skills, an established project with 11,060 GitHub stars
- Works with Claude Code
- Actively maintained — repository updated in the last 90 days
Author
Topics
Frequently asked questions
- What does javascript-pro do?
- 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.
- How do I install javascript-pro?
- Run /plugin marketplace add Jeffallan/claude-skills in your agent, then reload your skills. Review the source at https://github.com/Jeffallan/claude-skills before installing.
- Is javascript-pro free to use?
- Yes. javascript-pro is free and open source under the MIT license, so you can read, run, and adapt it within that license's terms.
- Which agents does javascript-pro work with?
- javascript-pro lists Claude Code — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does javascript-pro come from?
- javascript-pro ships inside Jeffallan/claude-skills, a repository that contains 41 catalogued skills in total. The repository's 11,060 GitHub stars apply to that whole collection, not to this skill on its own.