18Chesapeake

A web implementation of the 18xx-family game 18Chesapeake, written as a TypeScript monorepo.

The repository is split into two npm workspaces:

• engine/ — @18ai/engine, a pure TypeScript, framework-free game engine (no Angular, no rxjs, no DOM). It exposes apply(state, action) → state, initialState(), action serialization, and rule helpers. Deterministic given (initialState, actionLog).
• frontend/ — @18ai/frontend, the Angular application that renders the board, drives the UI, and dispatches actions through the engine. Built with Angular Material + CDK and standalone components.

A future backend/ workspace will host a Rails 7 API that persists the action log and brokers ActionCable broadcasts; per the chosen architecture (Pattern 1) the engine remains client-authoritative and the server is a dumb pipe.

The full design — coordinates, catalogs, action shape, persistence, multiplayer, AI — is documented in docs/architecture.md. That document is the single source of truth; this README is intentionally short.

Conceptual debt to tobymao/18xx is acknowledged in docs/architecture.md §16 — the de-facto reference 18xx implementation in Ruby/Opal. We are not porting it line-for-line, but several data shapes converge because the domain itself dictates them.

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Prerequisites

• Node.js — version pinned in .nvmrc (current Active LTS, Node 24 "Krypton" as of April 2026). With nvm: nvm use.
• npm ≥ 10 (ships with the pinned Node).

Install

From the repo root, install all workspace dependencies in one shot:

npm install

This installs both engine/ and frontend/ and symlinks @18ai/engine into node_modules so the frontend resolves it as a workspace dependency.

Run the engine tests

npm test -w engine

Vitest, strict TypeScript, ESLint, and Prettier are configured in engine/. Slice 1 ships with a single smoke test that exercises the placeholder export to prove the toolchain works end-to-end.

Run the Angular dev server

npm start -w frontend

Defaults to http://localhost:4200/. The landing page renders the placeholder message imported from @18ai/engine, confirming the workspace wiring. Real game UI lands in subsequent slices.

Repository layout

18ai/
  package.json           # npm workspaces: ["engine", "frontend"]
  README.md              # this file
  .nvmrc, .editorconfig, .gitignore
  docs/
    architecture.md      # design source of truth
  resources/             # rulebook PDF, reference board SVG, board image
  engine/                # @18ai/engine — pure TS
  frontend/              # @18ai/frontend — Angular app

See docs/architecture.md §14 for the full build order; this checkout corresponds to slice 1 (repo skeleton), no game logic yet.