Map API Gateway to an express server

server.ts

import express from "express";
import * as handlers from "./express-handler";
import { connector } from "swagger-routes-express";
import { apis, apiKeys } from "./constants";
import { getExport } from "./api-gateway";
import { setOperationIds } from "./utils";
import { ApiDefinition } from "./types";

const makeApp = (): express.Express => {
  const app = express();
  app.use(express.json()); // allow json body
  apis.forEach(async name => {
    const key = apiKeys[name];
    const { body } = await getExport(key); // get api definition Buffer

    const rawDefinition: ApiDefinition = JSON.parse(body.toString());
    const apiDefinition = setOperationIds(rawDefinition); // add operation ids according to each lambda

    const connect = connector(handlers, apiDefinition, { onCreateRoute });
    connect(app); // attach the routes
  });
  return app;
};