type-express-endpoints

name	type-express-endpoints
description	Types Express route handlers in this project using generated contract namespaces (e.g. Drivers, Vehicles). Use when the user asks to type an Express endpoint, add TypeScript types to a route handler, or type request/response params in a *.routes.ts file.

Typing Express endpoints

Where types come from

File	What's in it
src/types/data-contracts.ts	Shared models: ErrorResponse, entity interfaces (DriverListItem, etc.) — symlink to contract/types/data-contracts.ts
src/types/<Domain>Route.ts	Per-domain namespaces with RequestParams, ResponseBody, RequestBody, RequestQuery — symlink to contract/types/<Domain>Route.ts

Pattern

Always provide all four generic parameters to Request. Never use {} or omit parameters.

import { ErrorResponse } from '../types/data-contracts';
import { Drivers } from '../types/DriversRoute';

router.get('/', async (
  req: Request<
    Drivers.GetDrivers.RequestParams,
    Drivers.GetDrivers.ResponseBody | ErrorResponse,
    Drivers.GetDrivers.RequestBody,
    Drivers.GetDrivers.RequestQuery
  >,
  res: Response<Drivers.GetDrivers.ResponseBody | ErrorResponse>,
) => { ... });

Rules

• Request<Params, ResBody, ReqBody, Query> — all four, always.
• res: Response<SuccessBody | ErrorResponse> — always union with ErrorResponse.
• Namespace comes from src/types/<Domain>Route.ts, e.g. Drivers, Vehicles, Customers.
• Operation name matches the route method, e.g. GetDrivers, CreateDriver, GetDriverById.
• ErrorResponse always from ../types/data-contracts.
• If RequestBody is never (GET), it still appears in Request<> explicitly.
• Do not define local types for RequestQuery, RequestBody, ResponseBody — use contract types. Local duplicates (e.g. GetCustomersHttpQuery, CustomerListItemResponse, PatchCustomerHttpBody) are redundant. Use Customers.GetCustomers.RequestQuery, Customers.GetCustomers.ResponseBody, Customers.PatchCustomer.RequestBody, etc. req.body is already typed via Request<> generics — no cast needed.