Composable trie based router

Usage no npm install needed!

<script type="module">
  import wayfarer from 'https://cdn.skypack.dev/wayfarer';


wayfarer stability

npm version build status test coverage downloads js-standard-style

Composable trie based router. It's faster than traditional, linear, regular expression-matching routers, although insignficantly, and scales with the number of routes.

If you're looking for a client-side router check out sheet-router. If you're looking for a server router check out server-router.


  • works with any framework
  • built for speed
  • minimal dependencies
  • extensible


$ npm install wayfarer


var wayfarer = require('wayfarer')

var router = wayfarer('/404')

router.on('/', () => console.log('/'))
router.on('/404', () => console.log('404 not found'))
router.on('/:user', (params) => console.log('user is %s', params.user))
router.on('/wildcard/*', (params) => console.log('wildcard path is %s', params.wildcard))

// => 'user is tobi'

// => '404 not found'

// => 'wildcard path is example/path'


Routers can be infinitely nested, allowing routing to be scoped per view. Matched params are passed into subrouters. Nested routes will call their parent's default handler if no path matches.

var r1 = wayfarer()
var r2 = wayfarer()

r2.on('/child', () => console.log('subrouter trix!'))
r1.on('/:parent', r2)

// => 'subrouter trix!'


Sometimes it's necessary to walk the trie to apply transformations.

var walk = require('wayfarer/walk')
var wayfarer = require('wayfarer')

var router = wayfarer()
router.on('/multiply', (x, y) => x * y)
router.on('/divide', (x, y) => x / y)

walk(router, (route, cb) => {
  var y = 2
  return function (params, x) {
    return cb(x, y)

router('/multiply', 4)
// => 8
router('/divide', 8)
// => 4


router = wayfarer(default)

Initialize a router with a default route. Doesn't ignore querystrings and hashes.

router.on(route, cb(params, [arg1, ...]))

Register a new route. The order in which routes are registered does not matter. Routes can register multiple callbacks. The callback can return values when called.

matchedRoute = router.match(route)

Matches a route and returns an object. The returned object contains the properties {cb, params, route}. This method does not invoke the callback of a route. If no route matches, the default route will be returned. If no default route matches, an error will be thrown.

val = router(route, [arg1, ...])

Match a route and execute the corresponding callback. Alias: router.emit(). Returns a values from the matched route (e.g. useful for streams). Any additional values will be passed to the matched route.


Wayfarer is built on an internal trie structure. If you want to build a router using this trie structure it can be accessed through require('wayfarer/trie'). It exposes the following methods:

  • trie = Trie() - create a new trie
  • node = trie.create(route) - create a node at a path, and return a node
  • node = trie.match(route) - match a route on the the trie and return a node
  • trie.mount(path, trie) - mount a trie onto a node at route

Known issues

multiple nested partials don't match

E.g. /:foo/:bar/:baz won't work. This is due Trie.mount() overriding child partial paths when mounted. I'll get around to fixing this at some point in the future, but if anyone wants to contribute a patch it'd most appreciated.


Why did you build this?

Routers like react-router are complicated solutions for a simple problem. In reality all that's needed is a methodless router that can define + match paths and can mount other routers to delegate requests.

Why isn't my route matching?

Wayfarer only compares strings. Before you pass in an url you probably want to strip it of querystrings and hashes using the pathname-match module.

See Also