#lang pollen
 

 ◊section[#:headline "Routedux — Routes the Redux Way"]{

 ◊img[#:alt "Route Dux" #:src "https://upload.wikimedia.org/wikipedia/commons/thumb/d/da/Ducks_crossing_the_road_sign.png/92px-Ducks_crossing_the_road_sign.png" #:align "right"]

 ◊a[#:href "https://badge.fury.io/js/routedux"]{◊img[#:src "https://badge.fury.io/js/routedux.svg"]}
 ◊a[#:href "https://travis-ci.org/cjdev/routedux"]{◊img[#:alt "Build Status" #:src "https://travis-ci.org/cjdev/routedux.svg?branch=master"]}

 
 Routedux routes URLs to Redux actions and vice versa.
 

 Your application doesn't need to know it lives in a browser, but your
 users want pretty urls and deep links.

 ◊section[#:headline "Wait, my application doesn't need to know it lives in a browser?"]{

 URLs are great for finding things on the internet.  But a single page
 application is not the same as a collection of resources that lives on
 a remote server.

 A single page application is a web application only in the sense that
 it lives on the web.  URLs are are not essential to it working well.

 URLs give users accessing your application in a browser the ability to
 bookmark a particular view in your application so that their
 expectation of browser-based applications will continue to work.

 We think that's a good thing, but we also don't think the idea of url
 paths should be littered through your application.

 When you are developing a redux application, you want your UI to be a
 pure function of the current state tree.
 
 By adding routes to that, it makes it harder to test.  And this
 difficulty can be compounded by other decisions about how

 to add routes to your application.

 }

 ◊section[#:headline "An alternative approach"]{

 React Router is the currently-accepted way to do URL routing in React
 applications.  For a standard React application without Redux, this
 solution isn't too bad.  But once you add Redux, things get difficult.
 
 We basically discovered the same lessons as Formidable Labs:◊sidenote["REACTROUTERWRONG"]{
 ◊a[#:href
 "http://formidable.com/blog/2016/07/11/let-the-url-do-the-talking-part-1-the-pain-of-react-router-in-redux/"]{React
 Router is the wrong way to route in Redux apps.}}  However, we don't
 think their solution (◊a[#:href
 "https://github.com/FormidableLabs/redux-little-router"]{redux-little-router})
 goes far enough, as it still embeds the idea of routes throughout your
 user interface.
 
 Once you separate URLs from your application state, you can easily
 port it to other environments that don't know what URLs are, and by
 simply removing the routing declaration, things will work as before.
 
 As an added (and we think absolutely essential) benefit, your entire
 application becomes easier to test, as rendering is a pure function of
 Redux state, and model logic and route actions are entirely
 encapsulated in Redux outside of the app.}
 

 ◊section[#:headline "Demo Site"]{
 We have a demo codebase at ◊a[#:href "https://github.com/cjdev/routedux-docs-demo"]{demo repository}.
 
 }◊section[#:headline "Simple Routing in 25 lines"]{

 ◊pre{
 ◊code[#:class "javascript"]{

 import installBrowserRouter from 'routedux';

 import {createStore, compose} from 'redux';

 
 const LOAD_USER = 'LOAD_USER';
 
 function currentUserId() {
   return 42;
 };
 
 function reduce(state = initialState(), action) {
   ...
 }
 
 const routesConfig = [
   ['/user/:id', LOAD_USER, {}],
   ['/user/me', LOAD_USER, {id: currentUserId()}],
   ['/article/:slug', 'LOAD_ARTICLE', {}],
   ['/', 'LOAD_ARTICLE', {slug: "home-content"}]
 ];
 

 const {enhancer} = installBrowserRouter(routesConfig);

 
 const store = createStore(reduce, compose(

   enhancer

 ));

 }}

 Any time a handled action fires the url in the address bar will
 change, and if the url in the address bar changes the corresponding
 action will fire (unless the action was initiated by a url change).

 }

 ◊section[#:headline "Route matching precedence - which route matches best?"]{

 Route precedence is a function of the type of matching done in each
 segment and the order in which the wildcard segments match.  Exact
 matches are always preferred to wildcards moving from left to right.

 ◊pre{
 ◊code[#:class "javascript"]{

 const routesInOrderOfPrecedence = [
   ['/user/me/update', '/user/me'], // both perfectly specific - will match above any wildcard route
   '/user/me/:view',
   '/user/:id/update', // less specific because 'me' is exact match, while :id is a wildcard
   '/user/:id/:view'
 ];

 }}
 }

 ◊section[#:headline "Fragment component"]{

 Given that every UI state will be in your state tree as a function of
 your reducer logic, you can express any restriction on which parts of
 the UI display, even those that have nothing to do with the specific
 transformations caused by your URL actions.
 

 ◊pre{
 ◊code[#:class "javascript"]{

 const state = {
   menu: ...
 }
 
 const view = (
   <PageFrame>
       <Fragment state={state} filterOn="menu">
         <Menu />
       </Fragment>
   </PageFrame>
 )
 
 // If menu is truthy, this renders as:
 (
   <PageFrame>
     <Menu />
   </PageFrame>
 )
 
 // If menu is falsy, this renders as:
 (
   <PageFrame>
   </PageFrame>
 )
 
 // If property is missing in path, it's falsy.
 const view = (
   <PageFrame>
       <Fragment state={state} filterOn="menu.missingProp.something">
         <Menu />
       </Fragment>
   </PageFrame>
 )
 
 // Renders as:
 (
   <PageFrame>
   </PageFrame>
 )

 }}

 }
 
 ◊section[#:headline "ActionLink and pathForAction(action)"]{
 Occasionally it is nice to render URLs inside of your application.
 

 As a convenience, we have attached ◊code[#:class "javascript"]{pathForAction}
 to the ◊code[#:class "javascript"]{store} object, which uses the same
 matcher that the action matcher uses.  This allows you to create links
 in your application by using the actions.

 
 ◊pre{
 ◊code[#:class "javascript"]{
 const routesConfig = [
   ['/user/:id', LOAD_USER, {}],
   ['/user/me', LOAD_USER, {id: currentUserId()}]
 ];

 /* ... do store initialization */

 store.pathForAction({type:LOAD_USER, id: currentUserId()});

 /* returns /user/me */

 /* ActionLink */

 import { ActionLink as _ActionLink } from "routedux";

 const store = createStore(...);
 
 class ActionLink extends _ActionLink {
     constructor(props) {
         super({ ...props });
         this.store = store;
     }
 }
 
 const action = {
   type: LOAD_USER,
   id: 123
 };
 
 return (
   <ActionLink action={action}>Link Text</ActionLink>
 );
 
 /* renders as a link to <a href="/usr/123">Link Text</a> with the text */

 }}
 }

 Now you have links, but your links always stay up to date with your
 routing configuration.

 }