modern-javascript-patterns

modern-javascript-patterns is a skill for Claude Code, Codex from KunanonJ/ai-skills-hub. It costs 38 tokens per session (325 once invoked), scanned A, a copy of modern-javascript-patterns, MIT.

A guide to modern JavaScript features and coding patterns, including Promises, async/await, functional programming, and data transformation pipelines.

In plain words
What is it for?
Use it when refactoring legacy JavaScript, building web applications, improving performance, or migrating callback-based code to Promises and async/await.
Why use it?
It helps replace older or harder-to-maintain code with clearer patterns and reduces common problems in asynchronous code and performance-sensitive applications.

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/kunanonj/ai-skills-hub/modern-javascript-patterns
Any agent
npx skills add KunanonJ/ai-skills-hub --skill modern-javascript-patterns
Clone the repo
git clone --depth 1 https://github.com/KunanonJ/ai-skills-hub

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for modern-javascript-patterns

README.md
[![agentmods](https://agentmods.dev/badge/skills/kunanonj/ai-skills-hub/modern-javascript-patterns.svg)](https://agentmods.dev/skills/kunanonj/ai-skills-hub/modern-javascript-patterns)
Your own site
<a href="https://agentmods.dev/skills/kunanonj/ai-skills-hub/modern-javascript-patterns"><img src="https://agentmods.dev/badge/skills/kunanonj/ai-skills-hub/modern-javascript-patterns.svg" alt="Measured on agentmods" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 325 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 98% copy Near-identical to another mod 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 $0.00038 $0.00325
Opus 5 $0.00019 $0.00162
Sonnet 5 $0.00008 $0.00065
Haiku 4.5 $0.00004 $0.00032

Measured 5d ago against content hash 47d11a273455, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

modern-javascript-patterns 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 5d ago.

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.

Origin

This is a copy

98% identical to modern-javascript-patterns — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/modern-javascript-patterns/SKILL.md · 44 lines

What it actually says

Modern JavaScript Patterns

Comprehensive guide for mastering modern JavaScript (ES6+) features, functional programming patterns, and best practices for writing clean, maintainable, and performant code.

Use this skill when

  • Refactoring legacy JavaScript to modern syntax
  • Implementing functional programming patterns
  • Optimizing JavaScript performance
  • Writing maintainable and readable code
  • Working with asynchronous operations
  • Building modern web applications
  • Migrating from callbacks to Promises/async-await
  • Implementing data transformation pipelines

Do not use this skill when

  • The task is unrelated to modern javascript patterns
  • You need a different domain or tool outside this scope

Instructions

  • Clarify goals, constraints, and required inputs.
  • Apply relevant best practices and validate outcomes.
  • Provide actionable steps and verification.
  • If detailed examples are required, open resources/implementation-playbook.md.

Resources

  • resources/implementation-playbook.md for detailed patterns and examples.

Limitations

  • Use this skill only when the task clearly matches the scope described above.
  • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
  • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
Files

What ships with it

1 file 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. 5d ago First seen · 44 lines · 38 tokens per session scan A 47d11a273455

Subscribe to this mod's changes

modern-javascript-patterns is a skill published in the GitHub repository KunanonJ/ai-skills-hub (4 stars, last pushed 1mo ago), licensed MIT. It adds 38 tokens to every session and 325 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 98% identical to modern-javascript-patterns, differing in 1 line, and is treated as a copy.

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