Type Reference

The template includes full TypeScript type definitions for the Subway Builder Modding API v1.0.0. Here's how they're organized.

File Structure#

Types are split across multiple .d.ts files in src/types/, grouped by API namespace:

File	What it covers
`api.d.ts`	The main `ModdingAPI` interface — ties everything together
`index.d.ts`	Re-exports all types + declares `window.SubwayBuilderAPI`
`core.d.ts`	Primitives: `Coordinate`, `BoundingBox`, `GameSpeed`, `BuildType`, `ElevationType`
`game-state.d.ts`	Entity types: `Station`, `Track`, `Train`, `Route`, `DemandData`, ridership types
`game-constants.d.ts`	`GameConstants`, `ConstructionCosts`, `HighSlopeSpeedMultiplier`
`game-actions.d.ts`	`Bond`, `BondType`, `BondResult`
~~`build.d.ts`~~	~~Build automation: `BlueprintTrackInput`, `PlaceBlueprintResult`, `CreateRouteOptions`, etc.~~
`ui.d.ts`	UI system: `UIPlacement`, button/toggle/slider/panel option types
`cities.d.ts`	`City`, `CityConfig`, `CityTab`, `CityDataFiles`, `ViewState`
`trains.d.ts`	`TrainTypeConfig`, `TrainTypeStats`
`stations.d.ts`	`StationTypeConfig`
`map.d.ts`	Map types: `MapSource`, `MapLayer`, `TileURLOverride`, `RoutingServiceOverride`
`career.d.ts`	`MissionConfig`, `StarConfig`, `CareerMetrics`, `CareerOperators`
`content-templates.d.ts`	`NewspaperTemplate`, `TweetTemplate`
`pop-timing.d.ts`	`CommuteTimeRange`
~~`storage.d.ts`~~	~~Mod storage: `set`, `get`, `delete`, and `keys` methods for persistent mod data storage~~
`i18n.d.ts`	`I18nAPI`
`utils.d.ts`	`RechartsComponents`
`schemas.d.ts`	`GameSchemas` (Zod validation schemas)
`electron.d.ts`	`ElectronAPI`, `ElectronAPIExtended`
`manifest.d.ts`	`ModManifest`

Warning

The build/storage API types are listed on the official API documentation but are currently unusable at runtime.

How It Works#

index.d.ts re-exports everything and declares the global Window interface:

declare global {
  interface Window {
    SubwayBuilderAPI: ModdingAPI;
    electron?: ElectronAPI;
    electronAPI?: ElectronAPIExtended;
  }
}

This gives you full autocomplete when you type window.SubwayBuilderAPI. in your editor.

Key Types at a Glance#

Game Entities#

interface Station {
  id: string;
  name: string;
  coords: [number, number]; // [longitude, latitude]
  trackIds: string[];
  routeIds: string[];
  nearbyStations: NearbyStation[];
  buildType: string;
  createdAt: number;
  // ...
}
 
interface Track {
  id: string;
  coords: [number, number][]; // Start and end points
  trackType: string; // 'heavy-metro', 'light-metro', etc.
  startElevation: number;
  endElevation: number;
  length: number;
  // ...
}
 
interface Route {
  id: string;
  bullet: string; // Display label ('A', '1', etc.)
  color: string; // Hex color
  stations: RouteStation[];
  trainIds: string[];
  // ...
}
 
interface Train {
  id: string;
  routeId: string;
  position: Coordinate;
  speed: number;
  // ...
}

Core Primitives#

type Coordinate = [number, number]; // [longitude, latitude]
type BoundingBox = [number, number, number, number]; // [minLng, minLat, maxLng, maxLat]
type GameSpeed = 'slow' | 'normal' | 'fast' | 'ultrafast';
type BuildType = 'blueprint' | 'built';

UI Types#

type UIPlacement =
  | 'settings-menu'
  | 'escape-menu'
  | 'escape-menu-buttons'
  | 'main-menu'
  | 'bottom-bar'
  | 'top-bar'
  | 'debug-panel'
  | 'menu-items'
  | 'pause-menu'
  | 'debug';
 
type NotificationType = 'success' | 'error' | 'info' | 'warning';

Extending Types#

If you need to extend the API types (e.g., adding fields you've discovered at runtime), you can use TypeScript declaration merging in your own .d.ts file:

// src/types/my-extensions.d.ts
declare module './game-state' {
  interface Station {
    myCustomField?: string;
  }
}

Official Documentation#

For the most up-to-date API reference, see the official Subway Builder modding docs.