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javascript-fundamentals — Claude Code skill: guide and install

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

Install into Claude Code · Skills CLI (Vercel) All methods and platforms ↓ 
npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a claude-code
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What javascript-fundamentals 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.

What it helps with

  • 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 for the agent

  • 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.

How to install javascript-fundamentals

1Skills CLI (Vercel)

npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a claude-code

2Manually: put the files in place

~/.claude/skills/javascript-fundamentals/SKILL.md

Copy the whole skill folder; for one project use .claude/skills/javascript-fundamentals/

Step by step, with commands for each platform: How to install skills in Claude Code: five ways

Questions about javascript-fundamentals

How to install javascript-fundamentals in Claude Code?

Run npx skills add manutej/luxor-claude-marketplace --skill javascript-fundamentals -a claude-code. The CLI places the skill definition into your project configuration.

What does javascript-fundamentals do?

It grounds your coding assistant in core language rules. The model uses it to review syntax, explain scopes, and avoid antipatterns.

Does this skill need runtime libraries?

No. It operates entirely as Markdown prompt instructions without external npm packages.

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