Vercel / server.ts

Vercel detects a server entrypoint at the project root that calls server.listen(), and routes requests to it. It receives Node’s IncomingMessage/ServerResponse, so it takes a context object like the Node example.

Steps

npm install @drashland/drash
npm install --global vercel

import {
  Application,
  Resource,
} from "@drashland/drash/modules/http.polyfill.js";
import { createServer } from "node:http";
 
class Home extends Resource {
  paths = ["/"];
 
  GET(context) {
    context.response.end("Oh so easy");
  }
}
 
const app = Application
  .builder()
  .resources(Home)
  .build();
 
const server = createServer((request, response) => {
  const context = {
    url: `http://${request.headers.host ?? "localhost"}${request.url}`,
    method: request.method,
    request,
    response,
  };
 
  return app
    .handle(context)
    .catch((error) => {
      response.statusCode = 500;
      response.statusMessage = "Internal Server Error";
      response.end("Sorry, but we hit an error!");
    });
});
 
server.listen(Number(process.env.PORT ?? 3000));

vercel dev

Notes

url must be absolute. request.url from node:http is path-only (/users/1), which is why the example builds it from the host header — a bare path will not match.

The port passed to server.listen() is only used when you run the file locally. On Vercel it is ignored; requests are routed through an internal port.

Vercel Functions run on the Node runtime, whose URLPattern support varies by Node version, so this uses the polyfill entry point.

If you are writing plain JavaScript rather than TypeScript, set "type": "module" in your package.json or name the file .mjs. The polyfill entry point is an ES module, and Vercel does not allow require in these functions.

For the other Vercel entrypoint, see api/ (fetch).