Be aware that Accountant relies on the browser's HTML5 history, so older
browsers will be left behind.

## Installation

Just add the following to your `project.clj`:

```clojure
:dependencies [venantius/accountant "0.2.5"]
```

## Usage

All you have to do to get Accountant working is the following:

```clojure
(ns your-app-ns
(:require [accountant.core :as accountant]))

(accountant/configure-navigation!
{:nav-handler (fn [path] ...)
:path-exists? (fn [path] ...)})
```

The `:nav-handler` value is a fn of one argument, the path we're about to navigate to. You'll want to make whatever side-effect you need to render the page here. If you're using secretary, it'd look something like:

```clojure
(fn [path]
(secretary/dispatch! path))
```

If you're using bidi + just rendering via react, that might look like:

```clojure
(fn [path]
(om/update! app [:path] path))
```

The `:path-exists?` value is a fn of one argument, the path that we're about to navigate to.
The fn should return truthy if the path is
handled by your SPA, because accountant will call `event.preventDefault()` to
prevent the browser from doing a full page request.

Using secretary, `:path-exists?` should have a value like:

```clojure
(fn [path]
(secretary/locate-route path))
```

Using bidi, it would look like:

```clojure
(fn [path]
(boolean (bidi/match-route app-routes path)))
```

By default, clicking a link to the currently active route will not trigger the
navigation handler. You can disable this behavior and always trigger the
navigation handler by setting `reload-same-path?` to true during configuration.

```clojure
(accountant/configure-navigation! {:nav-handler (fn [path] ...)
:path-exists? (fn [path] ...)
:reload-same-path? true})
```

You can also use Accountant to set the current path in the browser, e.g.

```clojure
(accountant/navigate! "/foo/bar/baz")
```

If you want to dispatch the current path, just add the following:

```clojure
(dispatch-current!)
```

Note that both `navigate!` and `dispatch-current!` can only be used after calling `configure-navigation!`

To cleanup the resources allocated by `configure-navigation!`, use `unconfigure-navigation!`. This is useful
in cases where you create a component that manages configuring navigation, and would like to be able to easily
start/stop it.

```clojure
(accountant/unconfigure-navigation!)
```

### Caveat: UI Frameworks
Sometimes links may be used nested within UI components, especially when using third-party wrappers, like [react-bootstrap](https://react-bootstrap.github.io/) etc. These links may have an empty `href` attribute or a value like `#`. Two things might happen: Either, if a route is defined for the root path (i.e. '/' or '/#'), accountant will suppress the browser navigation and dispatch via secretary or the browser will reload the page.

To prevent this accountant looks for an attribute `data-trigger` on every link. The presence of this attribute signals that this link is a means to trigger a callback, not a navigation. If `data-trigger` is defined on a link it gets completely ignored, just like a button.

```clojure
(let [dropdown-button (reagent/adapt-react-class js/ReactBootstrap.DropdownButton)
menuitem (reagent/adapt-react-class js/ReactBootstrap.MenuItem)]
[dropdown-button {:id "foo" :title "..." :onSelect (fn [idx]...)}
[menuitem {:id "1"
:data-trigger true
:eventKey "1"}]
```

## License

Copyright © 2017 W. David Jarvis