# javascript-fundamentals

Supplies coding assistants with reference patterns for JavaScript syntax and language mechanics. It helps during refactoring, scope debugging, and code reviews.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 460 installs · ★ 62
- Author: manutej
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/manutej/luxor-claude-marketplace/tree/HEAD/plugins/luxor-frontend-essentials/skills/javascript-fundamentals/SKILL.md
- Updated: 2026-06-13
- HTML: https://affpapa.org/en/nevibecode/skills/javascript-fundamentals

## What it does

This skill injects language references into the coding agent. It covers variable scoping rules across `const`, `let`, and `var`, along with primitive type behavior and type checking. Guidance includes function declarations, arrow functions, and array transformations such as `map` or `reduce`.

The instructions detail prototypal inheritance via `Object.create` and data encapsulation patterns using closures. It directs the model away from common traps like accidental global variables or misinterpreting `this` context.

The skill relies purely on Markdown guidelines. It requires no runtime dependencies or third-party API tokens to function.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/javascript-fundamentals/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/javascript-fundamentals/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/javascript-fundamentals/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/javascript-fundamentals/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install manutej/luxor-claude-marketplace javascript-fundamentals
```

2. **Manually: put the files in place**
- File: `.github/skills/javascript-fundamentals/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/manutej/luxor-claude-marketplace --path plugins/luxor-frontend-essentials/skills/javascript-fundamentals
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/javascript-fundamentals/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/manutej/luxor-claude-marketplace/tree/HEAD/plugins/luxor-frontend-essentials/skills/javascript-fundamentals/SKILL.md

## When to use it
- modernize legacy codebases by replacing var with const and let
- implement private variables and data hiding through closures
- configure prototype chains between objects using Object.create
- select non-mutating array operations for predictable data flow

## Example prompts
- Refactor this function to replace the hoisted var declarations with proper block scopes.
- Create a factory function that keeps state private via a closure.
- Inspect this inheritance chain and wire the prototype methods correctly.

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From the same set: [manutej/luxor-claude-marketplace](https://affpapa.org/en/nevibecode/by/manutej/luxor-claude-marketplace.md) — 65 cards

---
NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md