Code Quality Tooling

The tools and what each one is for

Tool	Job
ESLint	Finds bugs and bad patterns in code (unused variables, hook rule violations, unsafe patterns) - static analysis, not formatting.
Prettier	Enforces one consistent formatting style (indentation, quotes, line width) so nobody argues about it in review - opinionated and mostly non-configurable by design.
Husky	Runs shell commands automatically at git lifecycle points (commit, push) - the mechanism, not the policy.
lint-staged	Runs a linter/formatter only against files that are actually staged for commit, not the whole repo - makes pre-commit checks fast.
commitlint	Rejects a commit message that doesn't match a required format.

ESLint (eslint.config.mjs)

Built from Next.js's own flat-config presets - eslint-config-next/core-web-vitals (React/Next.js correctness rules, including hook rules) and eslint-config-next/typescript (type-aware rules) - plus eslint-config-prettier to turn off any ESLint formatting rules that would otherwise conflict with Prettier.

One notable local override: the react-hooks plugin instance is pulled out of the Next.js preset (rather than adding it as a separate devDependency) specifically to disable two rules - react-hooks/set-state-in-effect and react-hooks/incompatible-library - with a comment noting they're off "until refactored," because they currently flag legitimate existing patterns (an async load() inside a useEffect, and react-hook-form's watch()). If you're touching code that trips one of these, that's a known, intentionally-silenced warning, not a new bug you introduced.

Terminal

pnpm lint

Prettier (prettier.config.mjs)

{
  plugins: ["prettier-plugin-tailwindcss"],
  semi: true, singleQuote: false, tabWidth: 4,
  trailingComma: "es5", printWidth: 100, endOfLine: "lf",
}

prettier-plugin-tailwindcss automatically sorts Tailwind utility classes into a canonical order inside className strings, so class order is never something to think about or bikeshed in review.

Terminal

pnpm format         # rewrite files in place
pnpm format:check   # check only, no writes - what CI runs

Git hooks (Husky)

Two hooks are installed under .husky/ (installed automatically via the prepare script, which runs on pnpm install):

Hook	Runs	Command
pre-commit	Every commit	pnpm exec lint-staged
commit-msg	Every commit	pnpm exec commitlint --edit $1

There is no pre-push hook - the test suite is not run locally on push. Tests are enforced in CI instead (see below), which is why a slow local push isn't blocked, but a broken PR still can't merge.

lint-staged (configured in package.json, not a separate file) determines what runs on which staged files:

"lint-staged": {
    "*.{ts,tsx,js,jsx,mjs,cjs}": ["eslint --fix", "prettier --write"],
    "*.{json,md,yml,yaml,css}": "prettier --write"
}

Commit messages (commitlint + Conventional Commits)

commitlint.config.cjs just extends @commitlint/config-conventional - no custom rules. Every commit message must follow type: description:

feat: add order export button
fix: minecraft whitelist not persisting
refactor: split auth helpers into separate module

Valid types: feat, fix, chore, docs, style, refactor, test, ci. A malformed message is rejected at commit time by the commit-msg hook, before it ever reaches a PR.

What CI enforces (.github/workflows/)

Workflow	Trigger	What it does
Code Quality	Push/PR → main	pnpm lint, pnpm format:check, pnpm tsc --noEmit
Tests	Push/PR → main	pnpm test
Deploy	Push → main	Pulls latest and runs scripts/deploy.sh on the self-hosted runner - see the Deployment guide

Both Code Quality and Tests must pass before a PR can merge (branch protection on main). Run pnpm check locally (lint + format check + typecheck) before pushing to catch what CI would catch, without waiting on CI.