Babel Config Skill

Purpose

Generate a Babel configuration file for transpilation in tests.

🔍 BEFORE GENERATING - RESEARCH CURRENT STANDARDS

⚠️ CRITICAL: Always verify current standards before generating. This skill may reference outdated conventions.

1. Check latest Babel documentation: https://babeljs.io/docs/configuration
2. Verify current config file format: Run npm view @babel/core version to check latest Babel version
3. Verify current preset package names: Check if @babel/preset-env, @babel/preset-typescript are still current
4. Check for deprecation warnings: Review latest Babel release notes for breaking changes
5. If standards have changed: Use NEW standards from official docs, NOT the examples below

🚨 MANDATORY FILE COUNT

Total Required: 1 file

• Babel config file (1 file) - extension may be .cjs, .mjs, .js, or .json depending on current standards

If this file is not created, test transpilation will FAIL.

Requirements (Dynamic - Verify Current Standards)

• Check current Babel best practices before generating
• Use latest recommended presets from official Babel documentation
• Use current standard file extension for Babel configs
• Verify package names exist in npm registry before adding: npm view <package> version
• If @babel/preset-env is deprecated, use its successor
• If .cjs extension is outdated, use current standard

Output

Create a Babel configuration file with the currently recommended format

Example Configuration (As of December 2025 - May be outdated)

⚠️ VERIFY these packages and conventions are still current before using:

Example File: babel.config.cjs

• Extension: .cjs (CommonJS format - verify this is still standard)
• Presets:
  • @babel/preset-env (for ES6+ transpilation - check if deprecated)
  • @babel/preset-typescript (for TypeScript - check if deprecated)
• Plugins:
  • @babel/plugin-transform-runtime (check if still recommended)

If any of these are deprecated or outdated:

• Check: https://babeljs.io/docs/ for current replacements
• Check: npm view @babel/core@latest for latest version info
• Check: Babel migration guides for breaking changes

Execution Checklist

Use this checklist to ensure the file is created:

• FIRST: Research current Babel standards (see "BEFORE GENERATING" section)
• Create Babel config file at project root (verify correct extension)
• File includes current standard presets for ES6+ and TypeScript
• File includes current standard plugins (if any)
• Verify packages exist in npm: npm view <package> version
• Verify file exists: ls babel.config.*

🛑 BLOCKING VALIDATION CHECKPOINT

STOP AND VERIFY before proceeding to the next skill:

Automated Verification (Flexible for any extension)

Run this command to verify the file exists:

# Check for babel config file (any valid extension)
if [ ! -f babel.config.cjs ] && [ ! -f babel.config.mjs ] && [ ! -f babel.config.js ] && [ ! -f babel.config.json ]; then
  echo "❌ MISSING: babel config file (expected: .cjs, .mjs, .js, or .json)"
  exit 1
fi
echo "✅ Babel config file present"

Manual Verification

1. ✓ Babel config file exists at project root (any current standard extension)
2. ✓ File contains current standard presets for ES6+ transpilation and TypeScript
3. ✓ File contains current standard plugins (if required)
4. ✓ All package names verified to exist: npm view <package> version
5. ✓ Configuration follows latest Babel documentation standards

If Validation Fails

DO NOT PROCEED to the next skill. Create the missing file immediately.

Notes

• Babel configuration for test environment transpilation (Jest/Vitest with Babel)
• Transpiles modern JavaScript for Node test environment
• File format depends on current Babel standards (check docs)
• Presets automatically determine necessary transformations
• Enables use of modern syntax in test files
• Required for test frameworks to process ES modules and modern JavaScript features
• Always verify current standards - Babel ecosystem evolves over time