Cap Buffet

Salary Cap Imagineering — a sport-agnostic salary-cap system constructor and compliance checker. Think "the NBA Trade Machine, but for cap-system construction." Compose a cap system out of reusable mechanic modules (hard cap, aprons, luxury tax, floor, max-contract rules, exceptions, revenue→cap formula…), load any roster, and see the cap sheet + whether it's legal and what penalties apply.

Because roster data and rulesets are fully decoupled, you can mix and match across leagues — "What would a second apron look like in the NFL? What if NBA teams had to use the hockey cap?" — and instantly find out.

It's a calculator, not a prescription. It computes the consequences of whatever rules you invent and passes no judgment on whether a cap design is good or fair. Financials are arbitrary — set the cap to $40 if you want. A minor league, the A-League, the CFL, a fantasy league — any scale works.

Run it

npm install
npm run dev        # dev server (Vite)
npm run build      # static build → dist/
npm run preview    # serve the built app
npm test           # engine unit tests (Vitest)

Fully client-side (React + TypeScript + Vite). No backend — all cap math runs in the browser and it deploys as a static site.

Deploy (Vercel / Netlify)

It's a static SPA, so hosting is zero-infrastructure. Config for both platforms is committed:

• Vercel — Import the repo at vercel.com/new. vercel.json sets the Vite framework preset, npm run build, dist/ output, and SPA fallback. Nothing to configure.
• Netlify — "Add new site → Import an existing project" at app.netlify.com. netlify.toml sets the build command, publish dir, Node version, and SPA redirect.

Either platform auto-builds on every push to the branch. The build is portable (relative asset paths via base: './'), so it also works from a GitHub Pages project subpath if you'd rather host there.

How it's built

The extensibility spine is a flat catalog of small mechanic modules, each keyed by a string kind. Inventing a mechanic = add one module + one catalog entry.

• src/engine/ — the pure, framework-free engine. evaluateRuleset(league, ruleset) → ComplianceReport, run per team/year in three phases (environment → charge → validate).
  • module.ts — the CapModuleDef interface + param schema (drives auto-generated forms).
  • catalog.ts — MODULE_CATALOG / MODULE_MAP registry.
  • modules/ — one file per mechanic (hardCap, luxuryTax, apron, maxContract, …).
  • serialize.ts — rulesets are plain JSON (save / load / share via URL hash).
• src/presets/ — the four majors plus MLS/NWSL/PWHL and a blank, each a Ruleset literal. The fact that real leagues are just presets is the proof the generator is real.
• src/data/rosters/ — sample rosters (decoupled from rulesets; any roster runs against any system).
• src/ui/ — the React app shell (sidebar palette · workspace ruleset builder · compliance panel).

There's also a second surface built on the same spine: the Expansion Draft tab (src/engine/expansion/), a rules constructor for expansion-draft models. Compose protection schemes, exemptions, exposure minimums, selection limits, rounds, and financial windows from the same kind of mix-and-match modules; load historical presets (NHL 2021, WNBA 2026 two-team, MLS, NBA 1988–2004, NFL 2002, MLB 1992/1997) or invent your own. It renders the model as a plain-language rulebook — with side-by-side comparison against any preset — and deliberately runs no "who would get picked" simulation. See docs/expansion-draft-plan.md.

Status

MVP: construct a cap system + check roster compliance, plus the expansion-draft rules constructor. A live trade/transaction sandbox, side-by-side system comparison, and the transaction-derived modules (proration/dead money, buyouts, retention, exceptions) are designed-for but deferred. See docs/mvp-plan.md.