@ultra-mega-apps/lint

Reusable ESLint config slices + custom rules for Ultra Mega Apps projects.

Install (monorepo local)

• Add as a workspace package (already in this repo):
  • Root package.json should include "lint" in workspaces.
  • Root devDependencies: "@ultra-mega-apps/lint": "file:./lint".

Usage

In your repo’s root eslint.config.mjs:

import path from "node:path";
import { includeIgnoreFile } from "@eslint/compat";
import { createConfig } from "@ultra-mega-apps/lint";

// Captured during install; edit as needed
const tsProjects = [
  // path.resolve("tsconfig.json"),
];

const base = createConfig({
  tsProjects,
  // testFiles default to ["**/*.test.ts", "**/*.spec.ts"]
  // tsconfigRootDir: process.cwd(), // Optional if you use relative tsconfig paths
});

export default [includeIgnoreFile(path.resolve(".gitignore")), ...base];

• Consumers may adjust tsProjects, testFiles, or linter options passed to createConfig.
• This package bundles ESLint, required plugins/configs (including eslint-plugin-jsx-a11y), Prettier, and TypeScript as dependencies, so consumers only need to install @ultra-mega-apps/lint.

What’s included

• Airbnb-based strict rules + Prettier integration
• TypeScript + React slices
• Custom rules:
  • empty-line-after/var blocks, let/const spacing
  • min identifier length
  • numeric literal separators
  • padding around braces/if/try
  • disallow nullish coalescing in returns
  • Playwright: disallow page.locator

Rule details

• pad-around-if: requires a blank line before if (except first in block or else if) and after standalone if when the next token is not }. A comment may appear directly above an if without an extra blank line.

Notes

• This package does not read .gitignore. Consumers decide ignore strategy (e.g., includeIgnoreFile).
• This package does not guess tsconfig paths; pass them in explicitly.

CLI

Run without installing anything in the target project (one-off fix):

npx @ultra-mega-apps/lint fix <dir>

Install and wire ESLint config + scripts into a project:

npx @ultra-mega-apps/lint install <dir>

This writes a minimal eslint.config.mjs with a literal tsProjects array discovered during install, adds lint and lint:fix scripts if missing, and runs npm i -D @ultra-mega-apps/lint.

Additionally, install will:

• Create an empty .gitignore if it does not exist (so the generated ESLint config can include it via includeIgnoreFile).
• Create or update .vscode/settings.json with "eslint.useFlatConfig": "auto" for a smoother VS Code experience with ESLint v9 flat config.
• Create or update prettierrc.json to ensure { "printWidth": 120 }.

To skip installing dependencies (useful in CI or when testing), pass:

npx @ultra-mega-apps/lint install <dir> --skip-deps