Enhance

The enhance helper provides a way to attach metadata to Middlewares and Handlers. This metadata can include routing information like path and method, as well as order for automatic middleware sequencing.

import { type Get, type UniversalHandler, enhance } from "@universal-middleware/core";

// A Universal Handler
const handler = (() => {
  return new Response("My homepage", {
    status: 200,
  });
}) satisfies UniversalHandler;

// Enhance a handler with HTTP method and path metadata
const enhancedHandler = (() => enhance(handler, {
  method: "GET", // Accepts a single method or array of methods: ["GET", "POST", "PATCH"]
  path: "/",     // Respects rou3 syntax. See https://github.com/unjs/rou3
  
  // The order property is specific to Middleware configuration
  // order: 10,  // Positive values execute AFTER handlers in the middleware chain
                 // Negative values execute BEFORE handlers in the middleware chain
})) satisfies Get<[], UniversalHandler>;

apply

The apply function is a helper exported by most adapters that:

• Reads metadata from enhanced middlewares/handlers (path, method, order)
• Automatically registers them with the framework-specific router in the correct order
• Handles route registration based on the path and method metadata
• Manages middleware sequencing based on the order property (negative orders run before handlers, positive after)

For example:

express.ts

import express from "express";
import { apply } from "@universal-middleware/express";

const app = express();

apply(app, [
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

hono.ts

import { Hono } from "hono";
import { apply } from "@universal-middleware/hono";

const app = new Hono();

apply(app, [
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

fastify.ts

import fastify from "fastify";
import { apply } from "@universal-middleware/fastify";

const app = fastify();

await apply(app, [
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

cloudflare-worker.ts

import { apply } from "@universal-middleware/cloudflare";

export default apply([
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

h3.ts

import { createApp } from "h3";
import { apply } from "@universal-middleware/h3";

const app = createApp();

apply(app, [
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

elysia.ts

import { Elysia } from "elysia";
import { apply } from "@universal-middleware/elysia";

const app = new Elysia();

apply(app, [
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

hattip.ts

import { createRouter } from "@hattip/router";
import { apply } from "@universal-middleware/hattip";

const app = createRouter();

apply(app, [
  // Register middleware and handlers in the application
  guardMiddleware(),
  // Each handler requires method and path metadata
  enhancedHandler(),
  // Handlers can be enhanced with different metadata for route variations
  enhance(enhancedHandler(), {
    method: ["GET", "POST"],
    path: "/home"
  })
]);

export default app.buildHandler();

Support status

The apply method is currently being rolled out across adapters. Some adapters require additional build-time steps before supporting this feature. We're actively working on expanding support to all adapters.

Adapter	Supported
express	✔️
hono	✔️
fastify	✔️
cloudflare-worker	✔️
cloudflare-pages	❌
vercel-edge	❌
vercel-node	❌
h3	✔️
elysia	✔️
hattip	✔️
webroute	❌