feat: Migrate ESLint configuration from root-only to per-package NX lint tasks

[Copilot]

Problem

Previously, this repository used NX for builds and tests but ESLint was configured to run from the root directory only. This meant:

• All linting had to run against the entire codebase, even when changes were made to just one package
• No caching benefits for linting - every lint run processed all files
• No ability to run linting on individual packages
• Slower CI and local development cycles

Solution

This PR migrates the ESLint configuration to use NX's per-package approach, enabling independent linting with caching for each library.

Key Changes

🔧 Added @nx/eslint plugin to provide NX-managed linting capabilities

📁 Per-package ESLint configurations - Each of the 11 packages now has its own .eslintrc.js file that extends the root configuration:

module.exports = {
  extends: ['../../.eslintrc.js'],
  root: false,
};

⚡ NX lint targets - All packages now have individual lint targets in their project.json files using the @nx/eslint:lint executor

📜 Updated scripts - Root package.json scripts now use NX:

• npm run lint → nx run-many --target=lint --all
• npm run lint:fix → nx run-many --target=lint --all --fix

🚀 Optimized caching - Added @nx/eslint:lint to targetDefaults in nx.json for proper cache configuration

Benefits

• Independent caching: Each package's lint results are cached separately by NX
• Faster builds: Only changed packages re-run linting (tested: "11 out of 11 tasks" read from cache)
• Parallel execution: Multiple packages can be linted simultaneously
• Granular control: Developers can lint specific packages with nx lint <package-name>
• Future extensibility: Easy to add package-specific lint rules when needed

Backward Compatibility

✅ lint-staged integration still works - continues using @codecademy/eslint-config/bin/eslint-fix.js for staged files
✅ husky pre-commit hooks continue to function normally
✅ Error reporting maintains the same behavior for failed lints
✅ Existing workflows remain unchanged

Usage Examples

# Lint all packages (with caching)
npm run lint

# Lint specific packages
nx lint gamut
nx lint styleguide

# Lint multiple specific packages
nx run-many --target=lint --projects=gamut,gamut-styles

# Fix linting issues
npm run lint:fix
nx lint styleguide --fix

The implementation maintains full compatibility with existing workflows while providing the performance and caching benefits of NX's per-package approach.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• cloud.nx.app
  • Triggering command: /usr/local/bin/node ./bin/post-install (dns block)
  • Triggering command: node /home/REDACTED/work/gamut/gamut/node_modules/.bin/nx run-many --target=build --projects=gamut --dry-run (dns block)
  • Triggering command: node /home/REDACTED/work/gamut/gamut/node_modules/.bin/nx build eslint-plugin-gamut (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

[nx-cloud]

View your CI Pipeline Execution ↗ for commit 51fc848

---

☁️ Nx Cloud last updated this comment at 2025-08-20 17:42:13 UTC

[CLAassistant]

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1 out of 2 committers have signed the CLA.

✅ jakemhiller
❌ Copilot
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[codecademydev]

📬Published Alpha Packages:

[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]
@codecademy/[email protected]

[codecademydev]

🚀 Styleguide deploy preview ready!

https://68a603013ee1152d70c8e903--gamut-preview.netlify.app

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