backend-template/packages/web-api/src/routes.ts

import { FastifyInstance } from 'fastify';
import { AdderController, AdderControllerImpl } from './modules/adder';

export const addRoutes = (server: FastifyInstance) => {
	const adderController: AdderController = new AdderControllerImpl();

	return server
		.route({
			method: 'POST',
			url: '/add',
			schema: {
				body: {
					type: 'object',
					properties: {
						a: { type: 'number' },
						b: { type: 'number' },
					}
				}
			},
			handler: adderController.addNumbers,
		})
		.route({
			method: 'POST',
			url: '/subtract',
			schema: {
				body: {
					type: 'object',
					properties: {
						a: { type: 'number' },
						b: { type: 'number' },
					}
				}
			},
			handler: adderController.subtractNumbers,
		});
};