A tiny URL router for Nano Stores state manager.

• Small. 838 bytes (minified and gzipped). Zero dependencies. It uses Size Limit to control size.
• It has good TypeScript support.
• Framework agnostic. Can be used for React, Preact, Vue, Svelte, and vanilla JS.

Since Nano Stores promote moving logic to store, the router is a store, not a component in UI framework like React.

// stores/router.ts
import { createRouter } from '@nanostores/router'

export const router = createRouter({
  home: '/',
  category: '/posts/:categoryId',
  post: '/posts/:categoryId/:postId'
})

Store in active mode listen for <a> clicks on document.body and Back button in browser.

// components/layout.tsx
import { useStore } from '@nanostores/react'

import { router } from '../stores/router.js'

export const Layout = () => {
  const page = useStore(router)

  if (!page) {
    return <Error404 />
  } else if (page.route === 'home') {
    return <HomePage />
  } else if (page.route === 'category') {
    return <CategoryPage categoryId={page.params.categoryId} />
  } else if (page.route === 'post') {
    return <PostPage postId={page.params.postId} />
  }
}

npm install nanostores @nanostores/router

See Nano Stores docs about using the store and subscribing to store’s changes in UI frameworks.

Routes is an object of route’s name to route pattern:

createRouter({
  route1: '/',
  route2: '/path/:var1/and/:var2',
  route3: [/\/posts\/(draft|new)\/(\d+)/, (type, id) => ({ type, id })]
})

For string patterns you can use :name for variable parts. To make the parameter optional, mark it with the ? modifier:

createRouter({
  routeName: '/profile/:id?/:tab?'
})

Routes can have RegExp patterns. They should be an array with function, which convert () groups to key-value map.

For TypeScript, router parameters will be converted to types automatically. You need to use TypeScript ≥5.x.

createRouter({
  routeName: '/path/:var1/and/:var2',
  routeName2: [/path2/, () => ({ num: 1, str: '' })]
})

/**
 * Params will be inferred as:
 * {
 *   routeName: { var1: string, var2: string },
 *   routeName2: { num: number, str: string }
 * }
 */

To use search query like ?a=1&b=2 in routes you need to set search option:

createRouter({
  home: '/p/?page=home'
}, {
  search: true
})

Router will works with ?search part as a string. Parameters order will be critical.

There is another store to watch for ?search parameters separately. It can be useful where ?search is used only as sub-routes for specific page. For instance, for filters settings on search page.

// stores/searchParams.ts
import { createSearchParams } from '@nanostores/router'

export const searchParams = createSearchParams()

// stores/searchResult.ts
import { searchParams } from '../searchParams'

export const searchResult = atom([])

onMount(searchResult, () => {
  return searchParams.subscribe(params => {
    searchResult.set(await search(params))
  })
})

function changeSearchParam(key: 'sort' | 'filter', value: string) {
  searchParams.set({ ...searchParams.get(), [key]: value })
}

By default, router and ?search params store will add click event listener on window to track links clicks.

You can disable this behavior by links: false options and create custom <Link> component.

export const router = createRouter({ … }, { links: false })

function onClick (e) {
  let link = event.target.closest('a')
  if (isPjax(link, e)) {
    router.open(new Url(link.href).pathname)
  }
}

export const Link = (props) => {
  return <a onClick={onClick} {...props}></a>
}

Using getPagePath() avoids hard coding URL in templates. It is better to use the router as a single place of truth.

import { getPagePath } from '@nanostores/router'

…
  <a href={getPagePath(router, 'post', { categoryId: 'guides', id: '10' })}>

If you need to change URL programmatically you can use openPage or redirectPage:

import { openPage, redirectPage } from '@nanostores/router'

function requireLogin () {
  openPage(router, 'login')
}

function onLoginSuccess() {
  // Replace login route, so we don’t face it on back navigation
  redirectPage(router, 'home')
}

Router can be used in Node environment without window and location. In this case, it will always return route to / path.

You can manually set any other route:

if (isServer) {
  router.open('/posts/demo/1')
}