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Yet Another React Router. (forked from Page.js a tiny ~1200 byte Express-inspired client-side router)

var yarr = require('yarr.js');

yarr('/', index)
yarr('/user/:user', show)
yarr('/user/:user/edit', edit)
yarr('/user/:user/album', album)
yarr('/user/:user/album/sort', sort)
yarr('*', notfound)
yarr()

examples

In order to provide suitable example, the original examples for page.js have been removed. New examples will be added to reflect the slightly modified behaviour. Please Note: Unlike in Page.js, you have to use yarr.Link for all links in React app for routing to work correctly. The Link Component has the same API as a normal <a> tag.

Changelog

v1.2.0

Link now uses React-Tappable behind the scenes. This means that you will get fast click responses on touch screens. The API on the outside remains unchanged.
Link now accepts any props that are accepted by React-Tappable. You can set the component attribute to use an element other than an <a> element. This includes custom React Classes. I have also submitted a pull request to React-Tappable that adds support for arbitrary props. I will update to the latest React-Tappable when that code is merged.
The previous version of Yarr.js only made the Link component available with a lowercase l. This is no longer the case. Link in capital case is now available as well. This means you can import the Link component in one of these ways:

var Link = require('yarr.js').Link;
var {Link} = require('yarr.js');
import {Link} from 'yarr.js';

API

yarr(path, callback[, callback ...])

Defines a route mapping path to the given callback(s).

yarr('/', user.list)
yarr('/user/:id', user.load, user.show)
yarr('/user/:id/edit', user.load, user.edit)
yarr('*', notfound)

Then with your react code use the yarr.link for any internal routable links.

var Link = require('yarr').link;

//use it as follows:
Link({href:'/my-route'}, "click here");

//or in JSX:
<Link href="/my-route">click here</Link>

yarr(callback)

This is equivalent to yarr('*', callback) for generic "middleware".

yarr(path)

Navigate to the given path.

  yarr('/user/12')

yarr.show(path)

Identical to yarr(path) above.

yarr([options])

popstate bind to popstate [true]
dispatch perform initial dispatch [true]

If you wish to load serve initial content from the server you likely will want to set dispatch to false.

yarr.start([options])

Identical to yarr([options]) above.

yarr.stop()

Unbind both the popstate and click handlers.

yarr.base([path])

Get or set the base path. For example if yarr.js is operating within "/blog/*" set the base path to "/blog".

Context

Routes are passed Context objects, these may be used to share state, for example ctx.user =, as well as the history "state" ctx.state that the pushState API provides.

Context#save()

Saves the context using replaceState(). For example this is useful for caching HTML or other resources that were loaded for when a user presses "back".

Context#canonicalPath

Pathname including the "base" (if any) and query string "/admin/login?foo=bar".

Context#path

Pathname and query string "/login?foo=bar".

Context#querystring

Query string void of leading ? such as "foo=bar", defaults to "".

Context#pathname

The pathname void of query string "/login".

Context#state

The pushState state object.

Context#title

The pushState title.

Routing

The router uses the same string-to-regexp conversion that Express does, so things like ":id", ":id?", and "*" work as you might expect.

Another aspect that is much like Express is the ability to pass multiple callbacks. You can use this to your advantage to flatten nested callbacks, or simply to abstract components.

Separating concerns

For example suppose you had a route to edit users, and a route to view users. In both cases you need to load the user. One way to achieve this is with several callbacks as shown here:

yarr('/user/:user', load, show)
yarr('/user/:user/edit', load, edit)

Using the * character we could alter this to match all routes prefixed with "/user" to achieve the same result:

yarr('/user/*', load)
yarr('/user/:user', show)
yarr('/user/:user/edit', edit)

Likewise * may be used as catch-alls after all routes acting as a 404 handler, before all routes, in-between and so on. For example:

yarr('/user/:user', load, show)
yarr('*', function(){
  // render not found
})

Default 404 behaviour

By default when a route is not matched, yarr.js will invoke yarr.stop() to unbind itself, and proceed with redirecting to the location requested. This means you may use yarr.js with a multi-page application without explicitly binding to certain links.

Working with parameters and contexts

Much like request and response objects are passed around in Express, yarr.js has a single "Context" object. Using the previous examples of load and show for a user, we can assign arbitrary properties to ctx to maintain state between callbacks.

First to build a load function that will load the user for subsequent routes you'll need to access the ":id" passed. You can do this with ctx.params.NAME much like Express:

function load(ctx, next){
  var id = ctx.params.id
}

Then perform some kind of action against the server, assigning the user to ctx.user for other routes to utilize. next() is then invoked to pass control to the following matching route in sequence, if any.

function load(ctx, next){
  var id = ctx.params.id
  $.getJSON('/user/' + id + '.json', function(user){
    ctx.user = user
    next()
  })
}

The "show" function might look something like this, however you may render templates or do anything you want. Note that here next() is not invoked, because this is considered the "end point", and no routes will be matched until another link is clicked or yarr(path) is called.

function show(ctx){
  React.renderComponent({user:ctx.user.name}, document.body);
}

Finally using them like so:

yarr('/user/:id', load, show)

Working with state

When working with the pushState API, and thus yarr.js you may optionally provide state objects available when the user navigates the history.

For example if you had a photo application and you performed a relatively expensive search to populate a list of images, normally when a user clicks "back" in the browser the route would be invoked and the query would be made yet-again.

Perhaps the route callback looks like this:

function show(ctx){
  $.getJSON('/photos', function(images){
    displayImages(images)
  })
}

You may utilize the history's state object to cache this result, or any other values you wish. This makes it possible to completely omit the query when a user presses back, providing a much nicer experience.

function show(ctx){
  if (ctx.state.images) {
    displayImages(ctx.state.images)
  } else {
    $.getJSON('/photos', function(images){
      ctx.state.images = images
      ctx.save()
      displayImages(images)
    })
  }
}

NOTE: ctx.save() must be used if the state changes after the first tick (xhr, setTimeout, etc), otherwise it is optional and the state will be saved after dispatching.

Matching paths

Here are some examples of what's possible with the string to RegExp conversion.

Match an explicit path:

yarr('/about', callback)

Match with required parameter accessed via ctx.params.name:

yarr('/user/:name', callback)

Match with several params, for example /user/tj/edit or /user/tj/view.

yarr('/user/:name/:operation', callback)

Match with one optional and one required, now /user/tj will match the same route as /user/tj/show etc:

yarr('/user/:name/:operation?', callback)

Use the wildcard char * to match across segments, available via ctx.params[N] where N is the index of * since you may use several. For example the following will match /user/12/edit, /user/12/albums/2/admin and so on.

yarr('/user/*', loadUser)

Named wildcard accessed, for example /file/javascripts/jquery.js would provide "/javascripts/jquery.js" as ctx.params.file:

yarr('/file/:file(*)', loadUser)

And of course RegExp literals, where the capture groups are available via ctx.params[N] where N is the index of the capture group.

yarr(/^\/commits\/(\d+)\.\.(\d+)/, loadUser)

Pull Requests

Break commits into a single objective.
An objective should be a chunk of code that is related but requires explaination.
Commits should be in the form of what-it-is: how-it-does-it and or why-it's-needed or what-it-is for trivial changes
Pull requests and commits should be a guide to the code.

In specific I would love:

Tests
Examples
Bug Fixes

License

(The MIT License)

Original Page.js by: TJ Holowaychuk <tj@vision-media.ca>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.