universal-middleware

Write middlewares and handlers once, target Hono, Express, Cloudflare, Hattip, Webroute, Fastify, h3, Elysia Vercel , (and more on the way!).

Documentation

Learn more on the Documentation

Code example

A middleware that returns an early response if some header is missing.

1// src/middlewares/demo.middleware.ts
2
3import type { Get, UniversalMiddleware } from "@universal-middleware/core";
4
5interface Config {
6  header: string;
7}
8
9// This middleware will return an early response if given header is missing
10const guardMiddleware = ((config) => (request, ctx) => {
11  if (!request.headers.has(config.header)) {
12    return new Response("Header not present", {
13      status: 401,
14    });
15  }
16  // else we do nothing
17
18  // Using `satisfies` to not lose return type
19}) satisfies Get<[Config], UniversalMiddleware>;
20
21// export default is mandatory
22export default guardMiddleware;

After bundling and publishing, this would be used like this:

1// hono-entry.ts
2
3import { Hono } from "hono";
4// hattip users would use "some-lib/middlewares/demo-middleware-hattip"
5// express users would use "some-lib/middlewares/demo-middleware-express"
6// etc.
7import demoMiddleware from "some-lib/middlewares/demo-middleware-hono";
8
9const app = new Hono();
10
11app.use(demoMiddleware({ header: 'X-Universal-Demo' }));
12app.get("/", () => new Response('ok')));
13
14export default app;