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Fact Check

leonardomso/33-js-concepts

This is built specifically for the 33 JavaScript Concepts project to catch technical errors before they ship. It walks you through five verification phases: running code examples against tests, checking MDN compliance, validating against the ECMAScript spec for edge cases, and verifying external links still work. The methodology is thorough, maybe overkill for a blog post, but exactly right if you're maintaining educational content where incorrect output comments or outdated pre-ES6 patterns could confuse thousands of learners. It even flags common mistakes like claiming typeof null returns "null" or getting Promise microtask timing wrong. Worth adapting if you publish any kind of technical reference material.

skills.sh installs
334
GitHub stars
66.5K
last updated
Aug 21, 2026
View on GitHub

Install

$ npx -y skills add leonardomso/33-js-concepts --skill fact-check --agent claude-code

Installs into .claude/skills of the current project.

Files

Skill: JavaScript Fact Checker

Use this skill to verify the technical accuracy of concept documentation pages for the 33 JavaScript Concepts project. This ensures we're not spreading misinformation about JavaScript.

When to Use

  • Before publishing a new concept page
  • After significant edits to existing content
  • When reviewing community contributions
  • When updating pages with new JavaScript features
  • Periodic accuracy audits of existing content

What We're Protecting Against

  • Incorrect JavaScript behavior claims
  • Outdated information (pre-ES6 patterns presented as current)
  • Code examples that don't produce stated outputs
  • Broken or misleading external resource links
  • Common misconceptions stated as fact
  • Browser-specific behavior presented as universal
  • Inaccurate API descriptions

Fact-Checking Methodology

Follow these five phases in order for a complete fact check.

Phase 1: Code Example Verification

Every code example in the concept page must be verified for accuracy.

Step-by-Step Process
SKILL.md on GitHub

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Details

Repository
github.com/leonardomso/33-js-concepts
First seen
Jun 3, 2026

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