Using itty-router to extract route info from Request or URL string

in http, node, ecmascript, javascript, router, route-matching

I wanted to extract route info from a Request, without executing any code on match. itty-router can do this, but getting it to work actually made me read the documentation since all my LLMs completely failed me.

router.js

First, create a router with handlers that just return the info you want using the createHandler factory function. This is based on the "complete example" in the itty-router docs. createHandler takes a single, optional argument that names the route. When omitted, the matched route pattern is used instead.

//router.js
import { AutoRouter } from 'itty-router'

const createHandler = (name) => {
  return ({ params, query, method, route }) => ({
    name: name || route,
    params,
    query,
    method,
    route,
  })
}

const router = AutoRouter({
  format: () => {},
  missing: createHandler('404'),
})

router
  .get('/', createHandler('index'))
  .get('/hello/:name', createHandler('sayHello'))

export default { ...router }

Using the router

Then, in your actual code, use it like this:

import router from './router.js'

//...

// assuming you already have a Request object
const result = await router.fetch(req)

Creating a Request object

If you don't have a Request object, you can either create one like this:

import router from './router.js'

const req = new Request('https://example.com/hello/world?foo=bar', {
  method: 'GET',
})

const result = await router.fetch(req)

Using itty-router's RequestLike

Or use itty-router's RequestLike interface:

import router from './router.js'

const req = {
  url: 'https://example.com/hello/world?foo=bar',
  method: 'GET',
}

const result = await router.fetch(req)

The result

The result object will contain the matched route information for you to use:

{
  name: 'sayHello',
  params: { name: 'world' },
  query: { foo: 'bar' },
  method: 'GET',
  route: '/hello/:name'
}