TypeScript

TypeScript > Routes & Routers - itty-router

One of the most basic things you'll likely find yourself typing with itty is simply the request itself, while defining routes.

This can be done in one of several ways, and almost always involves extending one of two very important types in itty, IRequest or IRequestStrict (a stricter version).

In general:

• Use IRequest (default) when you want to be able to access undefined attributes on a request.
• Use IRequestStrict when you want to only use defined attributes on a request.

1. At the variable

We can of course, simply type each argument in a handler. The first argument, request, defaults to IRequest unless overridden.

import { IRequest, Router } from 'itty-router'

type FooRequest = {
  foo: string
} & IRequestStrict

const router = Router()

router.get('/', (request: FooRequest) => { 
  request.foo // foo is valid
  request.bar // but bar is not
})

2. At the route (using generics)

Alternatively, we can move this to a generic at the route level.

import { IRequest, Router } from 'itty-router'

type FooRequest = {
  foo: string
} & IRequestStrict

const router = Router()

router.get<FooRequest>('/', (request) => { 
  request.foo // foo is valid
  request.bar // but bar is not
})

3. At the router level (using generics)

And finally, we can define the default request type for the entire router, again using a generic at the router creation.

import { IRequestStrict, Router } from 'itty-router'

type FooRequest = {
  foo: string
} & IRequestStrict

type BarRequest = {
  bar: string
} & IRequestStrict

const router = Router<FooRequest>() // router-level generic

router
  .get('/', (request) => {
    request.foo // foo is valid
    request.bar // but bar is not
  })

  // use a route-level generic to override the router-level one
  .get<BarRequest>('/', (request) => { // route-level override
    request.foo // now foo is not valid
    request.bar // but bar is
  })